A026917 a(n) = Sum{T(i,j)}, 0<=j<=i, 0<=i<=n, T given by A026907.

1, 27, 127, 399, 1039, 2439, 5383, 11439, 23743, 48567, 98455, 198495, 398863, 799911, 1602343, 3207567, 6418399, 12840471, 25685047, 51374655, 102754351, 205514247, 411034567, 822075759, 1644158719, 3288325239, 6576658903, 13153326879, 26306663503

Offset

0,2

Links

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (5,-9,7,-2).

Formula

a(n) = 98*2^n - 12*n^2 - 60*n - 97.

From Colin Barker, Feb 18 2016: (Start)

a(n) = 5*a(n-1)-9*a(n-2)+7*a(n-3)-2*a(n-4) for n>3.

G.f.: (1+22*x+x^2) / ((1-x)^3*(1-2*x)).

(End)

Mathematica

LinearRecurrence[{5, -9, 7, -2}, {1, 27, 127, 399}, 30] (* Harvey P. Dale, Jul 03 2017 *)

Prog

(PARI) Vec((1+22*x+x^2)/((1-x)^3*(1-2*x)) + O(x^40)) \\ Colin Barker, Feb 18 2016

Crossrefs

Sequence in context: A241755 A044359 A044740 * A267935 A048615 A124955

Adjacent sequences: A026914 A026915 A026916 * A026918 A026919 A026920

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved