共查询到20条相似文献,搜索用时 15 毫秒
1.
Jia Chaohua 《数学学报(英文版)》1993,9(3):321-336
LetP(x) denote the greatest prime factor of IIz<n≤x+x1/2
n. In this paper, we prove thatP(x)>x
0.723 holds true for a sufficiently largex.
Project supported by the Tian Yuan Itam in the National Natural Science Foundation of China. 相似文献
2.
Let N be a positive integer and let A and B be dense subsets of {1,...,N }. The purpose of this paper is to establish a good lower bound for the greatest prime factor of ab + 1as a and b run over the elements of A and B respectively. 相似文献
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We prove that for integers b>c>0$">, the greatest prime factor of tends to infinity with . In particular, this settles a conjecture raised by Györy, Sarkozy and Stewart, predicting the same conclusion for the product .
6.
K. Matomäki 《Acta Mathematica Hungarica》2009,124(1-2):115-123
We prove that whenever $ \mathcal{A} $ and $ \mathcal{B} $ are dense enough subsets of {1, ..., N}, there exist a ∈ $ \mathcal{A} $ and b ∈ $ \mathcal{B} $ such that the greatest prime factor of ab + 1 is at least $ N^{1 + |\mathcal{A}|/(9N)} $ . 相似文献
7.
Étienne Fouvry 《印度理论与应用数学杂志》2014,45(5):583-632
We improve some results on the size of the greatest prime factor of the integers of the form ab + 1 where a and b belong to some general given finite sequences A and B with rather large density. 相似文献
8.
Jia Chaohua 《数学学报(英文版)》1994,10(4):369-387
In this paper, we shall prove that for a sufficiently large odd numberN, the equation
相似文献
9.
Jia Chaohua 《数学学报(英文版)》1991,7(2):135-170
In this paper, we shall prove that for a sufficiently large odd numberN, the equation
has solutions.
The Project Supported by National Natural Science Foundation of China 相似文献
10.
Janos Galambos 《Journal of Number Theory》1977,9(3):338-341
Let ?(N) > 0 be a function of positive integers N and such that ?(N) → 0 and N?(N) → ∞ as N → + ∞. Let NνN(n:…) be the number of positive integers n ≤ N for which the property stated in the dotted space holds. Finally, let g(n; N, ?, z) be the number of those prime divisors p of n which satisfy NZ?(N) ? p ? N?(N), 0 < z < 1 In the present note we show that for each k = 0, ±1, ±2,…, as N → ∞, limvN(n : g(n; N, ?, z) ? g(n + 1; N, ?z) = k) exists and we determine its actual value. The case k = 0 induced the present investigation. Our solution for this value shows that the natural density of those integers n for which n and n + 1 have the same number of prime divisors in the range (1) exists and it is positive. 相似文献
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The asymptotics for the number of representations ofN asN→∞ is expressed as the sum of a number havingk prime divisors and a product of two natural numbers. The asymptotics is found fork≤(2−ε) ln lnN and (2+ε) ln lnN≤k≤b ln lnN, whereε>0. The results obtained are uniform with respect tok.
Translated fromMatematicheskie Zametki, Vol. 59, No. 4, pp. 585–602, April, 1996.
This research was partially supported by the Russian Foundation for Basic Research under grant No. 93-01-00260. 相似文献
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14.
Koji Suzuki. 《Mathematics of Computation》2006,75(254):1015-1024
denotes the number of positive integers and free of prime factors . Hildebrand and Tenenbaum gave a smooth approximation formula for in the range , where is a fixed positive number . In this paper, by modifying their approximation formula, we provide a fast algorithm to approximate . The computational complexity of this algorithm is . We give numerical results which show that this algorithm provides accurate estimates for and is faster than conventional methods such as algorithms exploiting Dickman's function.
15.
Y. C. Wang 《Acta Mathematica Hungarica》2012,135(3):248-269
Let Hk\mathcal{H}_{k} denote the set {n∣2|n,
n\not o 1 (mod p)n\not\equiv 1\ (\mathrm{mod}\ p) ∀ p>2 with p−1|k}. We prove that when
X\frac1120(1-\frac12k) +e\leqq H\leqq XX^{\frac{11}{20}\left(1-\frac{1}{2k}\right) +\varepsilon}\leqq H\leqq X, almost all integers
n ? \allowbreak Hk ?(X, X+H]n\in\allowbreak {\mathcal{H}_{k} \cap (X, X+H]} can be represented as the sum of a prime and a k-th power of prime for k≧3. Moreover, when
X\frac1120(1-\frac1k) +e\leqq H\leqq XX^{\frac{11}{20}\left(1-\frac{1}{k}\right) +\varepsilon}\leqq H\leqq X, almost all integers n∈(X,X+H] can be represented as the sum of a prime and a k-th power of integer for k≧3. 相似文献
16.
M. B. Khripunova 《Mathematical Notes》1998,63(5):658-669
The asymptotics of sums of the form Στ(|bn−a|) (summation overn<N, ω(n)=k) is studied, whereω(n) is the number of distinct prime divisors ofn, andτ(n) is the number of all divisors.
Translated fromMatematicheskie Zametki, Vol. 63, No. 5, pp. 749–762, May, 1998.
In conclusion, the author wishes to express his gratitude to Professor N. M. Timofeev for valuable advice.
This research was supported by the Russian Foundation for Basic Research under grant No. 96-01-00502. 相似文献
17.
Guangshi Lü 《Journal of Number Theory》2008,128(4):805-819
In this paper, we are able to sharpen Hua's classical result by showing that each sufficiently large integer can be written as
18.
On sums of a prime and four prime squares in short intervals 总被引:1,自引:0,他引:1
Xian-Meng Meng 《Acta Mathematica Hungarica》2004,105(4):261-283
19.
Define to be the number of positive integers such that has no prime divisor larger than . We present a simple algorithm that approximates in floating point operations. This algorithm is based directly on a theorem of Hildebrand and Tenenbaum. We also present data which indicate that this algorithm is more accurate in practice than other known approximations, including the well-known approximation , where is Dickman's function.
20.
On sums of a prime and four prime squares in short intervals 总被引:1,自引:1,他引:0
In this paper, we prove that each sufficiently large integer N ≠1(mod 3) can be written as N=p+p1^2+p2^2+p3^2+p4^2, with
|p-N/5|≤U,|pj-√N/5|≤U,j=1,2,3,4, where U=N^2/20+c and p,pj are primes. 相似文献 |