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 A020231 Strong pseudoprimes to base 5. 20
 781, 1541, 5461, 5611, 7813, 13021, 14981, 15751, 24211, 25351, 29539, 38081, 40501, 44801, 53971, 79381, 100651, 102311, 104721, 112141, 121463, 133141, 141361, 146611, 195313, 211951, 216457, 222301, 251521, 289081, 290629, 298271, 315121 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..715 from R. J. Mathar) Eric Weisstein's World of Mathematics, Strong Pseudoprime MATHEMATICA nmax = 400000; 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}]]); A020231 = {}; n = 1; While[n < nmax, n = n+2; If[sppQ[n, 5] == True, Print[n]; AppendTo[A020231, n]]]; A020231 (* Jean-François Alcover, Oct 20 2011, after R. J. Mathar *) CROSSREFS Cf. A005936, A001262 (base-2 SPP), A020229 (base-3 SPP), A215568 (SPP to bases 2 & 5), A215566 (SPP to bases 3 & 5), A056915 (SPP to bases 2, 3 & 5), A074773 (SPP to bases 2, 3, 5 & 7). Sequence in context: A250952 A139400 A115467 * A141390 A038477 A236888 Adjacent sequences:  A020228 A020229 A020230 * A020232 A020233 A020234 KEYWORD nonn AUTHOR STATUS approved

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Last modified September 19 02:22 EDT 2020. Contains 337175 sequences. (Running on oeis4.)