A213775 Principal diagonal of the convolution array A213774.

1, 11, 38, 97, 213, 432, 833, 1555, 2838, 5097, 9045, 15904, 27761, 48171, 83174, 143009, 244997, 418384, 712465, 1210195, 2050966, 3468681, 5855333, 9867072, 16600993, 27889547, 46790438, 78401185, 131212533, 219355632

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,-4,-2,4,0,-1).

Formula

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

G.f.: f(x)/g(x), where f(x) = x*(1 + 7*x - 2*x^2 - 9*x^3 - 5*x^4) and g(x) = (1 - 2*x + x^3 )^2.

Mathematica

(See A213774.)

Crossrefs

Cf. A213774, A213500.

Sequence in context: A143109 A007585 A024202 * A133258 A288745 A103738

Adjacent sequences: A213772 A213773 A213774 * A213776 A213777 A213778

Keyword

nonn,easy

Author

Clark Kimberling, Jun 21 2012

Status

approved