OFFSET
0,3
COMMENTS
If n > 0 then a(2n-1) = A021067(n).
a(n) = 0 if and only if n == -1 (mod 12).
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,3,0,-4,0,3,0,-1).
FORMULA
G.f.: -(x^6+3*x^5-5*x^4-2*x^3+x^2-x-1)/(x^8-3*x^6+4*x^4-3*x^2+1). - Alois P. Heinz, Feb 07 2021
MATHEMATICA
a[0] = 1; a[1] = 1; a[n_] := a[n] = a[n - 2] + (-1)^n a[n - 1] + n (1 - (-1)^n); Array[a, 100]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
José María Grau Ribas, Feb 07 2021
STATUS
approved