Table of n, a(n) for n=0..5.
Masao Koike, Modular forms on non-compact arithmetic triangle groups, Unpublished manuscript [Extensively annotated with OEIS A-numbers by N. J. A. Sloane, Feb 14 2021.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: A282437 A285150 A221289 * A155813 A220119 A178023
Adjacent sequences: A341559 A341560 A341561 * A341563 A341564 A341565
Robert C. Lyons, Feb 14 2021