On strong pseudoprimes to several bases
On strong pseudoprimes to several bases
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DOI:
10.1090/s0025-5718-1993-1192971-8
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发表时间:
1993-01
影响因子:
2
通讯作者:
G. Jaeschke
中科院分区:
文献类型:
--
作者:
G. Jaeschke
With Y'k denoting the smallest strong pseudoprime to all of the first k primes taken as bases we determine the exact values for 5, q6, q7, q8 and give upper bounds for V/9, / W t,' 1 . We discuss the methods and underlying facts for obtaining these results. 1. PRIMALITY TESTS BY MEANS OF STRONG PSEUDOPRIMES Computer algebra systems, as for instance AXIOM [2], use strong pseudoprimes for testing primality of integers. The advantage of such tests is that they are very efficient. The disadvantage is that they are only probabilistic tests when the integers are not restricted to certain intervals. To make such tests deterministic for integers in prescribed intervals, one has to know the exact number of necessary so-called "strong pseudoprimality tests". For this purpose we introduce the numbers V1i, V/2, . .. for which we compute lower and upper bounds. These numbers are defined and discussed in this section; in ?2 we derive some facts which are the basis for finding bounds for the numbers V/k. In ?3 we discuss the methods which led to our results. In view of Fermat's "Little Theorem" we know that n is certainly not a prime when we have bn-1 i 1 mod n for an integer b with 1 0, and when n is a composite number, then n is called a "strong pseudoprime to base b" if either