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 A120621 Least positive k such that !n + k is prime, where !n is left factorial. 1
 2, 1, 1, 1, 1, 3, 3, 3, 9, 3, 7, 9, 7, 13, 49, 27, 9, 37, 19, 33, 7, 93, 103, 9, 73, 27, 13, 27, 165, 49, 39, 93, 97, 27, 37, 39, 135, 7, 193, 249, 39, 103, 13, 33, 213, 129, 33, 13, 39, 115, 187, 19, 7, 387, 19, 489, 303, 63, 33, 235, 297, 495, 657, 465, 235, 193, 369, 129 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Amiram Eldar, Table of n, a(n) for n = 0..1000 MATHEMATICA a[n_] := Module[{k = 1, lf = Sum[i!, {i, 0, n - 1}]}, While[!PrimeQ[lf + k], k++]; k]; Array[a, 100, 0] (* Amiram Eldar, Dec 24 2019 *) CROSSREFS Cf. A003422, A033932 (with n! instead of !n). Sequence in context: A322494 A258445 A129179 * A201080 A039754 A213919 Adjacent sequences:  A120618 A120619 A120620 * A120622 A120623 A120624 KEYWORD easy,nonn AUTHOR Jason Earls, Aug 17 2006 STATUS approved

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Last modified November 28 13:47 EST 2021. Contains 349413 sequences. (Running on oeis4.)