A213832 Principal diagonal of the convolution array A213831.

1, 19, 78, 202, 415, 741, 1204, 1828, 2637, 3655, 4906, 6414, 8203, 10297, 12720, 15496, 18649, 22203, 26182, 30610, 35511, 40909, 46828, 53292, 60325, 67951, 76194, 85078, 94627, 104865, 115816, 127504

Offset

1,2

Links

Clark Kimberling, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Formula

G.f.: x*(1 + 15*x + 8*x^2)/(1-x)^4.

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4).

a(n) = (n - 7*n^2 + 8*n^3)/2.

a(n) = Sum_{i = 0..n-1} (n + i)*(n + 3*i). - Bruno Berselli, Feb 14 2018

Mathematica

(See A213831.)

Crossrefs

Cf. A213831.

Sequence in context: A304513 A041698 A041700 * A350194 A372757 A132234

Adjacent sequences: A213829 A213830 A213831 * A213833 A213834 A213835

Keyword

nonn,easy

Author

Clark Kimberling, Jul 04 2012

Status

approved