A065340 Third diagonal of triangle in A046740.

2, 28, 182, 864, 3474, 12660, 43358, 142552, 455930, 1430796, 4431078, 13595664, 41441570, 125732836, 380212142, 1147057800, 3454803594, 10393245180, 31240551350, 93849578560, 281817169202, 846013542228, 2539215029502, 7620094559544, 22865383949594

Offset

4,1

Links

Table of n, a(n) for n=4..28.

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

Cf. A046740.

Sequence in context: A347602 A006332 A280120 * A001798 A123787 A035601

Adjacent sequences: A065337 A065338 A065339 * A065341 A065342 A065343

Keyword

nonn,easy

Author

N. J. A. Sloane, May 15 2002

Extensions

More terms from Colin Barker, Feb 03 2013

Status

approved