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A213749 Antidiagonal sums of the convolution array A213747. 3
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified April 18 09:06 EDT 2021. Contains 343087 sequences. (Running on oeis4.)