A211457 Largest number b for which A181780(n) is a Fermat pseudoprime.

11, 13, 18, 25, 23, 29, 25, 37, 31, 35, 29, 34, 37, 55, 57, 49, 47, 51, 49, 49, 43, 81, 59, 88, 61, 56, 89, 97, 73, 81, 91, 109, 69, 118, 83, 25, 68, 85, 81, 125, 109, 95, 131, 133, 97, 137, 145, 67, 94, 107, 139, 142, 150, 134, 165, 151, 113, 119, 121, 179

Offset: 1

Author

T. D. Noe, Apr 13 2012

Keywords

• nonn

Comments

That is, the largest b for which b^(s-1) = 1 (mod s), where s is in A181780.

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A181780, A211455, A211456, A211458.

Programs

Mathematica

t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n], s = Select[Range[2, n-2], PowerMod[#, n-1, n] == 1 &]; If[s != {}, AppendTo[t, {n, Length[s], s}]]]]; Last/@Transpose[t][[3]]