OFFSET
0,2
FORMULA
EXAMPLE
G.f.: A(x) = 1 + 7*x + 56*x^2 + 273*x^3 + 1463*x^4 + 6048*x^5 + 26537*x^6 +...
where:
A(x) = (1+x+x^2)^7 * (1+x^2+x^4)^28 * (1+x^4+x^8)^112 * (1+x^8+x^16)^448 * (1+x^16+x^32)^896 *...* (1 + x^(2^n) + x^(2*2^n))^(7*4^n) *...
PROG
(PARI) {a(n)=local(A=1+x); for(i=1, #binary(n), A=(1+x+x^2)^7*subst(A^4, x, x^2) +x*O(x^n)); polcoeff(A, n)}
for(n=0, 50, print1(a(n), ", "))
(PARI) {a(n)=local(A=1+x); A=prod(k=0, #binary(n), (1+x^(2^k)+x^(2*2^k)+x*O(x^n))^(7*4^k)); polcoeff(A, n)}
for(n=0, 50, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, May 04 2014
STATUS
approved