OFFSET
4,2
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 - (3n+2)*2^(n-1) + 2n^2. - Ralf Stephan, May 09 2004
G.f.: -x^4*(12*x^5-40*x^4+39*x^3+9*x^2-11*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+2)*2^(n-1) + 2*n^2; \\ Michel Marcus, Oct 25 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, May 15 2002
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org), Oct 01 2002
More terms from Colin Barker, Feb 03 2013
STATUS
approved