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Masao Koike, Modular forms on non-compact arithmetic triangle groups, Unpublished manuscript [Extensively annotated with OEIS A-numbers by N. J. A. Sloane, Feb 14 2021.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 31.
Sequence in context: A000723 A020525 A252762 * A283017 A093189 A163430
Adjacent sequences: A341571 A341572 A341573 * A341575 A341576 A341577
Robert C. Lyons, Feb 15 2021