OFFSET
0,2
FORMULA
G.f.: A(x) = (1+x^2)/(1-x)^3 - [Sum_{n>=1} x^b(n)]/(1-x)^2, where b(n) = (2^(n+1) + 6*n + 3 + (-1)^n)/12.
EXAMPLE
A(x) = (1+x^2)/(1-x)^3 - [x+x^2+x^3+x^5+x^8+x^14+x^25+x^47+x^90+x^176+...]/(1-x)^2.
PROG
(PARI) {a(n)=polcoeff((1+x^2)/(1-x+x*O(x^n))^3 - sum(k=1, #binary(n)+2, x^((2^(k+1)+6*k+3+(-1)^k)/12))/(1-x +x*O(x^n) )^2, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Dec 16 2007
STATUS
approved