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 A001345 a(n) = Sum_{k = 0..3} (n+k)! C(3,k). (Formerly M4352 N1822) 4
 7, 16, 49, 212, 1158, 7584, 57720, 499680, 4843440, 51932160, 610001280, 7787404800, 107336275200, 1588369305600, 25113574886400, 422465999155200, 7533512034048000, 141940206600192000, 2817400117948416000, 58760985871171584000, 1284693905417674752000 (list; graph; refs; listen; history; text; internal format)
 OFFSET -1,1 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS T. D. Noe, Table of n, a(n) for n = -1..100 E. Biondi, L. Divieti, G. Guardabassi, Counting paths, circuits, chains and cycles in graphs: A unified approach, Canad. J. Math. 22 1970 22-35. MATHEMATICA Join[{7}, Table[Sum[(n + k)! Binomial[3, k], {k, 0, 3}], {n, 0, 20}]] (* T. D. Noe, Jun 28 2012 *) PROG (PARI) a(n) = if (n == -1, 7, sum(k=0, 3, (n+k)!*binomial(3, k))); \\ Michel Marcus, Jun 30 2017 CROSSREFS Cf. A001346, A001347. Sequence in context: A173661 A152530 A065099 * A225128 A056613 A318413 Adjacent sequences: A001342 A001343 A001344 * A001346 A001347 A001348 KEYWORD easy,nonn AUTHOR EXTENSIONS More terms from Sean A. Irvine, Jun 19 2012 STATUS approved

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Last modified November 27 03:04 EST 2022. Contains 358362 sequences. (Running on oeis4.)