A213749 Antidiagonal sums of the convolution array A213747.

1, 9, 46, 180, 603, 1827, 5164, 13878, 35905, 90189, 221274, 532584, 1261687, 2949255, 6815896, 15597738, 35389629, 79691985, 178258150, 396361980, 876609811, 1929380139, 4227858756, 9227469150, 20065550713, 43486544277, 93952410034, 202400334288

Offset

1,2

Links

Clark Kimberling, Table of n, a(n) for n = 1..500

Index entries for linear recurrences with constant coefficients, signature (9,-33,63,-66,36,-8).

Formula

a(n) = 9*a(n-1) - 33*a(n-2) + 63*a(n-3) - 66*a(n-4) + 36*a(n-5) - 8*a(n-6).

G.f.: x*(1 - 2*x^2) / ((1 - x)^3*(1 - 2*x)^3).

a(n) = (1/2)*((1+n)*(4-2^(2+n) + n + 2^(1+n)*n)). - Colin Barker, Oct 30 2017

Mathematica

(See A213747.)
LinearRecurrence[{9, -33, 63, -66, 36, -8}, {1, 9, 46, 180, 603, 1827}, 30] (* Harvey P. Dale, May 16 2013 *)

Prog

(PARI) Vec(x*(1 - 2*x^2) / ((1 - x)^3*(1 - 2*x)^3) + O(x^30)) \\ Colin Barker, Oct 30 2017

Crossrefs

Cf. A213747, A213500.

Sequence in context: A034487 A035039 A001926 * A085385 A217152 A081193

Adjacent sequences: A213746 A213747 A213748 * A213750 A213751 A213752

Keyword

nonn,easy

Author

Clark Kimberling, Jun 19 2012

Status

approved