0,3

E. Bannai, S. T. Dougherty, M. Harada and M. Oura, Type II Codes, Even Unimodular Lattices and Invariant Rings, IEEE Trans. Information Theory, Volume 45, Number 4, 1999, 1194-1205.

Index entries for linear recurrences with constant coefficients, signature (2, -1, 4, -8, 4, -6, 12, -6, 4, -8, 4, -1, 2, -1).

G.f.: (5*x^12 + 51*x^11 + 190*x^10 + 400*x^9 + 846*x^8 + 947*x^7 + 882*x^6 + 795*x^5 + 304*x^4 + 152*x^3 + 36*x^2 - x + 1)/((x - 1)^6*(x^2 + x + 1)^4).

a(n) ~ 64*n^5/135. - Stefano Spezia, Aug 21 2022

CoefficientList[Series[(5x^12+51x^11+190x^10+400x^9+846x^8+947x^7+882x^6+795x^5+304x^4+152x^3+36x^2-x+1)/((x-1)^6(x^2+x+1)^4), {x, 0, 40}], x] (* or *) LinearRecurrence[ {2, -1, 4, -8, 4, -6, 12, -6, 4, -8, 4, -1, 2, -1}, {1, 1, 37, 229, 721, 2152, 5083, 10167, 19637, 34575, 56511, 90552, 138093, 201909}, 40] (* Harvey P. Dale, Jul 14 2021 *)

Cf. A051461, A051462.

Sequence in context: A284987 A133958 A088544 * A275750 A142445 A155974

Adjacent sequences: A051460 A051461 A051462 * A051464 A051465 A051466

nonn,easy,nice

More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jun 15 2001

approved