

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
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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 2235.


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

N. J. A. Sloane


EXTENSIONS

More terms from Sean A. Irvine, Jun 19 2012


STATUS

approved



