A025774 - OEIS

A025774

Expansion of 1/((1-x)(1-x^4)(1-x^9)).

1, 1, 1, 1, 2, 2, 2, 2, 3, 4, 4, 4, 5, 6, 6, 6, 7, 8, 9, 9, 10, 11, 12, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 31, 32, 33, 34, 36, 38, 39, 40, 42, 44, 45, 46, 48, 50, 52, 53, 55, 57, 59, 60, 62

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OFFSET

0,5

LINKS

Table of n, a(n) for n=0..60.

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

FORMULA

a(0)=1, a(1)=1, a(2)=1, a(3)=1, a(4)=2, a(5)=2, a(6)=2, a(7)=2, a(8)=3, a(9)=4, a(10)=4, a(11)=4, a(12)=5, a(13)=6, a(n)=a(n-1)+a(n-4)-a(n-5)+ a(n-9)-a(n-10)-a(n-13)+a (n-14). - Harvey P. Dale, Nov 11 2013

a(n) = floor(((n^2+14*n+76)+18*cos((n-1)*Pi/2))/72). - Tani Akinari, May 02 2014

MATHEMATICA

CoefficientList[Series[1/((1-x)(1-x^4)(1-x^9)), {x, 0, 60}], x] (* or *) LinearRecurrence[{1, 0, 0, 1, -1, 0, 0, 0, 1, -1, 0, 0, -1, 1}, {1, 1, 1, 1, 2, 2, 2, 2, 3, 4, 4, 4, 5, 6}, 70] (* Harvey P. Dale, Nov 11 2013 *)

CROSSREFS

Sequence in context: A260731 A194239 A064475 * A280168 A001156 A199119

Adjacent sequences: A025771 A025772 A025773 * A025775 A025776 A025777

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved