A001346 a(n) = Sum_{k = 0..4} (n+k)! C(4,k). (Formerly M5134 N2225)

23, 65, 261, 1370, 8742, 65304, 557400, 5343120, 56775600, 661933440, 8397406080, 115123680000, 1695705580800, 26701944192000, 447579574041600, 7955978033203200, 149473718634240000, 2959340324548608000, 61578385989120000000, 1343454891288846336000

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[{23}, Table[Sum[(n + k)! Binomial[4, k], {k, 0, 4}], {n, 0, 20}]] (* T. D. Noe, Jun 28 2012 *)

Prog

(PARI) a(n) = if (n==-1, 23, sum(k=0, 4, (n+k)!*binomial(4, k))); \\ Michel Marcus, Jun 30 2017

Crossrefs

Cf. A001345, A001347.

Sequence in context: A304896 A316578 A323220 * A051875 A125872 A228611

Adjacent sequences: A001343 A001344 A001345 * A001347 A001348 A001349

Keyword

nonn

Author

N. J. A. Sloane

Status

approved