Two kinds of strong pseudoprimes up to 1036
Two kinds of strong pseudoprimes up to 1036
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DOI:
10.1090/s0025-5718-07-01977-1
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发表时间:
2007-10
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影响因子:
--
通讯作者:
Zhenxiang Zhang
中科院分区:
文献类型:
--
作者:
Zhenxiang Zhang
Let n > 1 be an odd composite integer. Write n - 1 = 2 s d with d odd. If either b d ≡ 1 mod n or b 2r d ≡ -1 mod n for some r = 0,1,..., s - 1, then we say that n is a strong pseudoprime to base b, or spsp(b) for short. Define ψ t to be the smallest strong pseudoprime to all the first t prime bases. If we know the exact value of ψ t , we will have, for integers n 10 36 ; and to give reasons and numerical evidence of K2- and C 3 -spsp's 12, where ψ' t (resp. ψ" t ) is the smallest K2- (resp. C 3 -) strong pseudoprime to all the first t prime bases. For this purpose we describe procedures for computing and enumerating the two kinds of spsp's < 10 36 to the first 9 prime bases. The entire calculation took about 4000 hours on a PC Pentium IV/1.8GHz. (Recall that a K2-spsp is an spsp of the form: n = pq with p, q primes and q - 1 = 2(p - 1); and that a C 3 -spsp is an spsp and a Carmichael number of the form: n = q 1 q 2 q 3 with each prime factor q i = 3 mod 4.).