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A020229 Strong pseudoprimes to base 3. 11
121, 703, 1891, 3281, 8401, 8911, 10585, 12403, 16531, 18721, 19345, 23521, 31621, 44287, 47197, 55969, 63139, 74593, 79003, 82513, 87913, 88573, 97567, 105163, 111361, 112141, 148417, 152551, 182527, 188191, 211411, 218791, 221761, 226801 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..752

Joerg Arndt, Matters Computational (The Fxtbook), section 39.10, pp. 786-792

Index entries for sequences related to pseudoprimes

Eric Weisstein's World of Mathematics, Strong Pseudoprime

MATHEMATICA

sppQ[n_?EvenQ, _] := False; sppQ[n_?PrimeQ, _] := False; sppQ[n_, b_] := (s = IntegerExponent[n-1, 2]; d = (n-1)/2^s; If[PowerMod[b, d, n] == 1, Return[True], Do[If[PowerMod[b, d*2^r, n] == n-1, Return[True]], {r, 0, s-1}]]); A020229 = {}; lst = {}; k = 3; While[k < 500000, If[sppQ[k, 3], Print[k]; AppendTo[lst, k]]; k += 2]; lst (* Jean-Fran├žois Alcover, Oct 20 2011, after R. J. Mathar *)

PROG

(PARI) is_A020229(n, b=3)={ bittest(n, 0)|return; ispseudoprime(n)&return; my(d=(n-1)>>valuation(n-1, 2)); Mod(b, n)^d==1 || until(n-1<=d*=2, Mod(b, n)^d+1 || return(1))}  \\  - M. F. Hasler, Jul 19 2012

CROSSREFS

Cf. A072276, A056915, A074773.

Sequence in context: A036306 A014749 A048950 * A141350 A235408 A190877

Adjacent sequences:  A020226 A020227 A020228 * A020230 A020231 A020232

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified November 21 21:29 EST 2014. Contains 249791 sequences.