A218165 a(n) is the smallest positive integer k such that k^128 + 1 == 0 mod p, where p is the n-th prime of the form 1 + 256*b (see A208178).

3, 7, 17, 198, 71, 88, 29, 50, 9, 225, 26, 141, 10, 79, 36, 89, 281, 108, 43, 233, 156, 412, 430, 296, 79, 20, 76, 178, 80, 54, 1018, 82, 89, 403, 85, 208, 914, 373, 1226, 62, 192, 68, 390, 1055, 1500, 137, 1018, 141, 95, 54, 160, 52, 11, 754, 674, 182, 517

Offset

1,1

Comments

A208178(n): primes of form 256n+1.

Links

Table of n, a(n) for n=1..57.

Example

a(1) = 3 because 3^128+1 = 2
* 257 * 275201 * 138424618868737 * 3913786281514524929 * 153849834
853910661121  with A208178(1) = 257.

Mathematica

aa = {}; Do[p = Prime[n]; If[Mod[p, 256] == 1, k = 1; While[ ! Mod[k^128 + 1, p] == 0, k++ ]; AppendTo[aa, k]], {n, 5000}]; aa

Crossrefs

Cf. A208178.

Sequence in context: A383027 A041949 A222452 * A384767 A102329 A331713

Adjacent sequences: A218162 A218163 A218164 * A218166 A218167 A218168

Keyword

nonn

Author

Michel Lagneau, Oct 22 2012

Status

approved