OFFSET
0,1
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 = 0..100
E. Biondi, L. Divieti, and G. Guardabassi, Counting paths, circuits, chains and cycles in graphs: A unified approach, Canad. J. Math. 22 1970 22-35.
FORMULA
a(n) = floor( n! * (n^4+6*n^3+17*n^2+20*n+9) * exp(1) ). [Mark van Hoeij, Nov 11 2009]
a(n) = Sum_{k=0..n} binomial(n, k)*(k+4)!. - Christian Krause, Dec 21 2022
MATHEMATICA
nn = 20; Range[0, nn]! CoefficientList[Series[24*Exp[x]/(1 - x)^5, {x, 0, nn}], x] (* T. D. Noe, Jun 28 2012 *)
PROG
(PARI) a(n) = n!*polcoeff(24*exp(x+x*O(x^n))/(1-x)^5, n) \\ Christian Krause, Dec 21 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Error in description corrected Jan 30 2008
More terms from N. J. A. Sloane, Jan 30 2008
STATUS
approved