OFFSET
1,6
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..1000
FORMULA
G.f.: -1 + (Product_{j>=1} (1 + x^(3*j)/(1-x^j)))/Product_{j>=1} (1 + x^(12*j)/(1-x^(4*j))). - Emeric Deutsch, Jun 21 2009
EXAMPLE
a(13)=5 because we have (3^3)(1^4), (2^5)(1^3), (2^4)(1^5), (2^3)(1^7), and 1^(13). - Emeric Deutsch, Jun 21 2009
MAPLE
g := -1+(product(1+x^(3*j)/(1-x^j), j = 1 .. 40))/(product(1+x^(12*j)/(1-x^(4*j)), j = 1 .. 40)): gser := series(g, x = 0, 70): seq(coeff(gser, x, n), n = 2 .. 68); # Emeric Deutsch, Jun 21 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 06 2009
STATUS
approved