A298757 Numbers k with record value of the least strong pseudoprime to base k (A298756).

2, 1320, 4712, 5628, 7252, 7852, 14787, 17340, 61380, 78750, 254923, 486605, 1804842, 4095086, 12772344, 42162995

Offset

1,1

Comments

The record strong pseudoprimes are 2047, 4097, 4711, 5627, 7251, 7851, 9409, 10261, 11359, 13747, 18299, 25761, 32761, 38323, 40501, 97921, ...

Links

Table of n, a(n) for n=1..16.

Index entries for sequences related to pseudoprimes

Mathematica

sppQ[n_?EvenQ, _] := False; sppQ[n_?PrimeQ, _] := False; sppQ[n_, b_] := Module[{ans=False}, s = IntegerExponent[n-1, 2]; d = (n-1)/2^s; If[ PowerMod[b, d, n] == 1, ans=True, Do[If[PowerMod[b, d*2^r, n] == n-1, ans=True], {r, 0, s-1}]]; ans]; smallestSPP[b_] := Module[ {k=3}, While[ !sppQ[k, b], k+=2]; k ]; sm=0; a={}; Do[s=smallestSPP[b]; If[s>sm, sm=s; AppendTo[a, b]], {b, 2, 10^4}]; a (* after Jean-François Alcover at A020229 *)

Prog

(PARI) lista(nn) = {my(m=0); for (n=2, nn, my(r=a298756(n)); if (r>m, m =r; print1(n, ", ")); ); } \\ Michel Marcus, Jan 31 2022; using pari code in A298756

Crossrefs

Cf. A001262, A020229, A020230, A020231, A020232, A020233, A020234, A020235, A298756.

Sequence in context: A062663 A295187 A345402 * A020526 A247821 A202866

Adjacent sequences: A298754 A298755 A298756 * A298758 A298759 A298760

Keyword

nonn,more

Author

Amiram Eldar, Jan 26 2018

Extensions

a(9)-a(16) from Jonathan Pappas, Jan 31 2022

Status

approved