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A020229
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Strong pseudoprimes to base 3.
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11
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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
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OFFSET
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1,1
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LINKS
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R. J. Mathar, Table of n, a(n) for n = 1..752
Joerg Arndt, Fxtbook, section 39.10, pp. 786-792
Index entries for sequences related to pseudoprimes
Eric Weisstein's World of Mathematics, Strong Pseudoprime
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MATHEMATICA
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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 (* From Jean-François Alcover, Oct 20 2011, after R. J. Mathar *)
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PROG
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(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
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CROSSREFS
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Cf. A072276, A056915, A074773.
Sequence in context: A036306 A014749 A048950 * A141350 A190877 A203959
Adjacent sequences: A020226 A020227 A020228 * A020230 A020231 A020232
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KEYWORD
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nonn
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AUTHOR
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David W. Wilson
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STATUS
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approved
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