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 A200920 Least k such that (3^n+ k)*3^n + 1 is a prime number. 5
 1, 3, 1, 5, 3, 25, 11, 5, 13, 13, 9, 7, 3, 9, 17, 7, 29, 25, 71, 49, 7, 9, 7, 9, 11, 39, 7, 25, 107, 3, 67, 59, 49, 89, 67, 29, 113, 5, 33, 7, 19, 53, 3, 5, 47, 121, 39, 7, 407, 25, 7, 215, 29, 23, 89, 5, 33, 25, 113, 45, 49, 109, 53, 17, 109, 311, 91, 145, 43 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS MATHEMATICA Table[k = 0; While[!PrimeQ[(3^n + k)*3^n + 1], k++]; k, {n, 72}] CROSSREFS Cf. A191617, A191618, A191619, A191620, A200921, A200922, A200923. Sequence in context: A171382 A002323 A294640 * A290534 A242639 A117853 Adjacent sequences:  A200917 A200918 A200919 * A200921 A200922 A200923 KEYWORD nonn AUTHOR Michel Lagneau, Nov 24 2011 STATUS approved

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Last modified June 14 21:27 EDT 2021. Contains 345041 sequences. (Running on oeis4.)