OFFSET
0,3
LINKS
C. Ahmed, P. Martin, and V. Mazorchuk, On the number of principal ideals in d-tonal partition monoids, arXiv preprint arXiv:1503.06718 [math.CO], 2015-2019.
B. N. Cyvin et al., Enumeration of conjugated hydrocarbons: Hollow hexagons revisited, Structural Chem., 6 (1995), 85-88, equations (6) and (22).
W. C. Huffman, The biweight enumerator of self-orthogonal binary codes, Discr. Math. Vol. 26 1979, pp. 129-143.
Index entries for linear recurrences with constant coefficients, signature (1,1,1,-2,-2,1,1,1,-1).
FORMULA
G.f.: 1 / ( (1+x)*(1+x+x^2)^2*(x-1)^4 ). - R. J. Mathar, Mar 22 2011
MAPLE
A117373 := proc(n) op(1+(n mod 6), [1, -2, -3, -1, 2, 3]) ; end proc:
A076118 := proc(n) coeftayl( x*(1-x)/(1-x+x^2)^2, x=0, n) ; end proc:
A028289 := proc(n) 1/108*n^3 +1/8*n^2 +55/108*n +29/48 +1/16*(-1)^n -2*(-1)^n*A117373(n+2)/27 +(-1)^n*A076118(n+1)/9; end proc:
seq(A028289(n), n=0..20) ; # R. J. Mathar, Mar 22 2011
MATHEMATICA
CoefficientList[Series[(1+x^2+x^3+x^5)/((1-x)(1-x^3)(1-x^4) (1-x^6)), {x, 0, 50}], x] (* Harvey P. Dale, Apr 20 2011 *)
PROG
(PARI) Vec((1+x^2+x^3+x^5)/((1-x)*(1-x^3)*(1-x^4)*(1-x^6))+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved