A025793 Expansion of 1/((1-x)*(1-x^10)*(1-x^11)).

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 8, 9, 10, 10, 10, 10, 10, 10, 10, 11, 12, 13, 14, 15, 15, 15, 15, 15, 15, 16, 17, 18, 19, 20, 21, 21, 21, 21, 21, 22, 23, 24, 25, 26, 27, 28, 28, 28, 28, 29, 30, 31, 32

Offset

0,11

Links

Table of n, a(n) for n=0..73.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,0,0,0,1,0,-1,0,0,0,0,0,0,0,0,-1,1).

Formula

a(n) = (n^2 + 22*n + 11*(2 + (n mod 10))*(10 - (n mod 10)) -10*(n mod 11)*(11 - (n mod 11)))/220. - Hoang Xuan Thanh, Aug 20 2025

Mathematica

CoefficientList[Series[1/((1-x)(1-x^10)(1-x^11)), {x, 0, 90}], x] (* or *) LinearRecurrence[ {1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 5}, 90] (* Harvey P. Dale, Apr 18 2024 *)

Prog

(PARI) Vec(1/((1-x)*(1-x^10)*(1-x^11)) + O(x^64)) \\ Hoang Xuan Thanh, Aug 20 2025

Crossrefs

Sequence in context: A185436 A025794 A354760 * A102680 A025791 A358474

Adjacent sequences: A025790 A025791 A025792 * A025794 A025795 A025796

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved