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A218164 a(n) is the smallest positive integer k such that k^64 + 1 == 0 mod p, where p is the n-th prime of the form 1 + 128*b (see A208177). 0
9, 21, 5, 38, 21, 31, 33, 63, 42, 66, 118, 131, 202, 29, 28, 31, 58, 171, 94, 182, 309, 182, 81, 272, 110, 175, 657, 491, 42, 100, 523, 244, 168, 199, 145, 138, 79, 73, 357, 826, 210, 541, 523, 215, 98, 220, 1478, 22, 92, 178, 50, 709, 250, 2523, 630, 218, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A208177 : primes of the form 128*k+1.

LINKS

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

EXAMPLE

a(1) = 9 because 9^64+1 = 2 * 257 * 275201 * 138424618868737 * 3913786281514524929 * 153849834853910661121 with A208177(1) = 257.

MATHEMATICA

spi[n_]:=Module[{k=1}, While[PowerMod[k, 64, n]!=n-1, k++]; k]; spi/@Select[128 Range[500]+1, PrimeQ] (* Harvey P. Dale, Jan 19 2021 *)

CROSSREFS

Cf. A208177.

Sequence in context: A008847 A143243 A157812 * A161326 A250783 A259250

Adjacent sequences:  A218161 A218162 A218163 * A218165 A218166 A218167

KEYWORD

nonn

AUTHOR

Michel Lagneau, Oct 22 2012

EXTENSIONS

Corrected by Harvey P. Dale, Jan 19 2021

STATUS

approved

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Last modified June 22 17:18 EDT 2021. Contains 345388 sequences. (Running on oeis4.)