OFFSET
4,1
LINKS
D. P. Roselle, Permutations by number of rises and successions, Proc. Amer. Math. Soc., 19 (1968), 8-16.
D. P. Roselle, Permutations by number of rises and successions, Proc. Amer. Math. Soc., 19 (1968), 8-16. [Annotated scanned copy]
Index entries for linear recurrences with constant coefficients, signature (10,-40,82,-91,52,-12).
FORMULA
a(n) = 3^n-(3*n+1)*2^(n-1)+2*n^2-2*n+1. - Vladeta Jovovic, Jan 04 2003
G.f.: -2*x^4*(9*x^2-4*x-1) / ((x-1)^3*(2*x-1)^2*(3*x-1)). [Colin Barker, Feb 03 2013]
PROG
(PARI) a(n) = 3^n-(3*n+1)*2^(n-1)+2*n^2-2*n+1; \\ Michel Marcus, Oct 25 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, May 15 2002
EXTENSIONS
More terms from Colin Barker, Feb 03 2013
STATUS
approved