A211456 Smallest base b for which A181780(n) is a Fermat pseudoprime.

4, 8, 7, 9, 10, 6, 14, 8, 18, 16, 9, 21, 20, 8, 8, 25, 22, 11, 26, 45, 34, 4, 28, 3, 32, 39, 10, 8, 38, 65, 24, 8, 50, 3, 40, 5, 57, 44, 61, 8, 26, 46, 12, 12, 50, 121, 8, 23, 61, 52, 22, 23, 19, 37, 49, 24, 49, 58, 62, 6, 97, 67, 55, 11, 14, 165, 68, 57, 9

Offset

1,1

Comments

That is, the smallest 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

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}]]]]; First/@Transpose[t][[3]]

Crossrefs

Cf. A181780, A211455, A211457, A211458.

Sequence in context: A247605 A244000 A201937 * A309665 A196205 A196141

Adjacent sequences: A211453 A211454 A211455 * A211457 A211458 A211459

Keyword

nonn

Author

T. D. Noe, Apr 13 2012

Status

approved