OFFSET
0,5
FORMULA
a(n) = A121652(n)^(1/3).
EXAMPLE
A(x) = 1 + x + x^2 + x^3 + 2*x^4 + 3*x^5 + 4*x^6 + 6*x^7 + 9*x^8 +...
The coefficients of 1 - 1/A(x) equal the cube of each term:
1/A(x) = 1 - x - x^4 - x^7 - x^10 - 8*x^13 - 27*x^16 - 64*x^19 - 216*x^22 -... - a(n)^3*x^(3*n+1) -...
PROG
(PARI) {a(n)=local(B); if(n==0, 1, B=sum(k=0, n\3, a(k)^3*x^(3*k)); polcoeff(1/(1-x*B+x*O(x^n)), n))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 14 2006
STATUS
approved