OFFSET
0,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (6,-18,38,-63,84,-92,84,-63,38,-18,6,-1).
FORMULA
G.f.: (x^2-x+1)*(x^4-2*x^3+6*x^2-2*x+1)/((x^2+1)^3*(x-1)^6).
a(n) = A282011(n+5,n).
a(n) = (1+n)*(2+n)*(3+n)*(4+n)*(5+n)/240 + ((-i)^n+i^n)*(8+6*n+n^2)/32 where i=sqrt(-1). - Colin Barker, Feb 06 2017
EXAMPLE
a(0) = 1: {}.
a(1) = 3: {2}, {4}, {6}.
a(2) = 9: {1,3}, {1,5}, {1,7}, {2,4}, {2,6}, {3,5}, {3,7}, {4,6}, {5,7}.
MATHEMATICA
LinearRecurrence[{6, -18, 38, -63, 84, -92, 84, -63, 38, -18, 6, -1}, {1, 3, 9, 28, 66, 126, 226, 396, 651, 1001, 1491, 2184}, 40] (* Harvey P. Dale, Sep 30 2019 *)
PROG
(PARI) Vec((x^2-x+1)*(x^4-2*x^3+6*x^2-2*x+1) / ((x^2+1)^3*(x-1)^6) + O(x^60)) \\ Colin Barker, Feb 06 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Feb 05 2017
STATUS
approved