OFFSET
1,1
COMMENTS
These are exactly the even integers 2n such that the group Gamma_0(2n)+n has genus zero.
LINKS
Miranda C. N. Cheng, John F. R. Duncan and Jeffrey A. Harvey, Umbral moonshine and the Niemeier lattices, Research in the Mathematical Sciences, 2014, 1:3. See Eq. (23).
FORMULA
a(n) = 2*A133848(n+11). - Omar E. Pol, Dec 20 2014
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
N. J. A. Sloane, Jun 19 2014
STATUS
approved