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).
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
Offset: 1
Keywords
Examples
a(1) = 9 because 9^64+1 = 2 * 257 * 275201 * 138424618868737 * 3913786281514524929 * 153849834853910661121 with A208177(1) = 257.
Crossrefs
Cf. A208177.
Programs
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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 *)
Extensions
Corrected by Harvey P. Dale, Jan 19 2021
Comments