OFFSET
0,2
LINKS
Michael Baake and Peter A. B. Pleasants, Algebraic solution of the coincidence problem in two and three dimensions, Zeitschrift für Naturforschung A 50.8 (1995): 711-717. See page 714.
EXAMPLE
The D.g.f. is 1 + 4/13^s + 2/25^s + 4/37^s + ... .
PROG
(PARI) a(n) = direuler(p = 2, 12*n-11, (1 + (p%12==1)*X)^2/(1 - (p%12==1)*X)^2 * (1 + ((p%12==5)+(p%12==7))*X^2)/(1 - ((p%12==5)+(p%12==7))*X^2))[12*n-11]; \\ Amiram Eldar, May 11 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 14 2019
EXTENSIONS
More terms from Amiram Eldar, May 11 2024
STATUS
approved