A074773 Strong pseudoprimes to bases 2, 3, 5 and 7.

3215031751, 118670087467, 307768373641, 315962312077, 354864744877, 457453568161, 528929554561, 546348519181, 602248359169, 1362242655901, 1871186716981, 2152302898747, 2273312197621, 2366338900801, 3343433905957, 3461715915661, 3474749660383, 3477707481751, 4341937413061, 4777422165601, 5537838510751

Offset: 1

Author

Don Reble, Sep 07 2002

Keywords

• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
• Washington Bomfim, Table with all 16757 terms up to 2^64
• G. Jaeschke, On strong pseudoprimes to several bases, Mathematics of Computation, 61 (1993), 915-926.
• Eric Weisstein's World of Mathematics, Miller's Primality Test
• Index entries for sequences related to pseudoprimes

Crossrefs

Cf. A001262, A020229, A020231, A020233, A056915.

Programs

PARI

sprp(n,b)=my(s=valuation(n-1,2),d=Mod(b,n)^(n>>s)); if(d==1, return(1)); for(i=1,s-1, if(d==-1, return(1)); d=d^2;); d==-1
is(n)=sprp(n,2) && sprp(n,3) && sprp(n,5) && sprp(n,7) && !isprime(n) \\ Charles R Greathouse IV, Sep 14 2015

Extensions

b-file, link, and editing from Charles R Greathouse IV, Aug 14 2010