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 A219341 Least prime k such that k*2^n + 1 divides 2^k - 1, or 0 if no such prime exists. 0
 2, 3, 0, 11, 397, 839, 1459, 2081, 7297, 53849, 3499, 70589, 792277, 20399, 11173873, 929057, 232591, 6782759, 5834299, 26812151, 40269673, 88529891, 368454343, 616767917, 1167319801, 709939943 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS If a(n) > 0, then a(n)*2^n + 1 is in A122094. LINKS Table of n, a(n) for n=0..25. G. L. Honaker, Jr. and Chris Caldwell, Prime Curios! 232591 Eric Weisstein's World of Mathematics, Mersenne Number MATHEMATICA lst = {}; Do[k = 2; If[n == 2, AppendTo[lst, 0], While[True, If[PrimeQ[k], f = k*2^n + 1; If[PrimeQ[f] && PowerMod[2, k, f] == 1, AppendTo[lst, k]; Break[]]]; k++]], {n, 0, 13}]; lst CROSSREFS Cf. A001348, A002144. Sequence in context: A012404 A002099 A265514 * A059740 A005160 A085042 Adjacent sequences: A219338 A219339 A219340 * A219342 A219343 A219344 KEYWORD more,nonn AUTHOR Arkadiusz Wesolowski, Nov 18 2012 STATUS approved

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Last modified May 29 19:17 EDT 2023. Contains 363042 sequences. (Running on oeis4.)