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

Author

N. J. A. Sloane, May 15 2002

Keywords

• nonn
• easy

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).

Crossrefs

Cf. A046740.

Programs

PARI

a(n) = 3^n-(3*n+1)*2^(n-1)+2*n^2-2*n+1; \\ Michel Marcus, Oct 25 2017

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]

Extensions

More terms from Colin Barker, Feb 03 2013