A341311 G.f. = (1+x^2+2*x^3+3*x^4+4*x^5+3*x^6+4*x^7+3*x^8+2*x^9+x^10)/(1-x^6)^2.

1, 0, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 33, 32, 33, 34, 35, 36, 37, 36, 37, 38, 39, 40, 41, 40, 41, 42, 43, 44, 45, 44, 45, 46

Offset

0,4

Links

Table of n, a(n) for n=0..69.

Masao Koike, Modular forms on non-compact arithmetic triangle groups, Unpublished manuscript [Extensively annotated with OEIS A-numbers by N. J. A. Sloane, Feb 14 2021. I wrote 2005 on the first page but the internal evidence suggests 1997.] See page 13, line 2.

Mathematica

CoefficientList[Series[(1 + x^2 + 2*x^3 + 3*x^4 + 4*x^5 + 3*x^6 + 4*x^7 + 3*x^8 + 2*x^9 + x^10)/(1 - x^6)^2, {x, 0, 300}], x]  (* Vincenzo Librandi, Mar 07 2021 *)

Crossrefs

Cf. A341307.

Sequence in context: A309064 A325631 A276073 * A284000 A309293 A244904

Adjacent sequences: A341308 A341309 A341310 * A341312 A341313 A341314

Keyword

nonn

Author

N. J. A. Sloane, Feb 15 2021

Status

approved