Table of n, a(n) for n=0..4.
Masao Koike, Modular forms on non-compact arithmetic triangle groups, Unpublished manuscript [Extensively annotated with OEIS A-numbers by N. J. A. Sloane, Feb 14 2021. Sloane wrote 2005 on the first page but the internal evidence suggests 1997.] See page 30.
Sequence in context: A296326 A064561 A291177 * A093761 A324458 A073873
Adjacent sequences: A341565 A341566 A341567 * A341569 A341570 A341571
Robert C. Lyons, Feb 15 2021