A275909 Expansion of (1+4*x+8*x^2+8*x^3+7*x^4+4*x^5+2*x^6) / (1-x-7*x^2-12*x^3-6*x^4-7*x^5-4*x^6-2*x^7).

1, 5, 20, 75, 288, 1094, 4171, 15897, 60565, 230816, 879521, 3351544, 12771524, 48667365, 185453453, 706693601, 2692945820, 10261812539, 39103937948, 149010523846, 567823518619, 2163763618201, 8245296020629, 31419747421972, 119728937140293, 456242317652464, 1738569283271528

Offset

0,2

Links

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

T. Doslic, T. Short, Maximal matchings in polyspiro and benzenoid chains, arXiv:1511.00590, [math.CO], 2015. See Th. 4.4.

Index entries for linear recurrences with constant coefficients, signature (1,7,12,6,7,4,2).

Formula

a(n) = 2*a(n-1)+6*a(n-2)+5*a(n-3)-6*a(n-4)+a(n-5)-3*a(n-6)-2*a(n-7)-2*a(n-8) for n>6. - Colin Barker, Aug 26 2016

Prog

(PARI) Vec((1+4*x+8*x^2+8*x^3+7*x^4+4*x^5+2*x^6)/(1-x-7*x^2-12*x^3-6*x^4-7*x^5-4*x^6-2*x^7) + O(x^30)) \\ Colin Barker, Aug 26 2016

Crossrefs

Sequence in context: A224422 A000344 A290922 * A275908 A290909 A270023

Adjacent sequences: A275906 A275907 A275908 * A275910 A275911 A275912

Keyword

nonn,easy

Author

N. J. A. Sloane, Aug 26 2016

Status

approved