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A063289
Dimension of the space of weight n cuspidal newforms for Gamma_1( 16 ).
1
-1, 2, 7, 11, 16, 20, 25, 29, 34, 38, 43, 47, 52, 56, 61, 65, 70, 74, 79, 83, 88, 92, 97, 101, 106, 110, 115, 119, 124, 128, 133, 137, 142, 146, 151, 155, 160, 164, 169, 173, 178, 182, 187, 191, 196, 200, 205, 209, 214, 218, 223, 227, 232, 236
OFFSET
2,2
COMMENTS
It appears that for n > 2 a(n) = floor((9n-22)/2). - Gary Detlefs, Mar 02 2010
FORMULA
a(n) = 9*n/2 + (-1)^n/4 - 45/4 for n >= 3, with first differences in A010710. - R. J. Mathar, Dec 06 2010
From M. F. Hasler, Mar 05 2012: (Start)
G.f.: x^2*(-1 + 3*x + 6*x^2 + x^3)/(1 - x - x^2 + x^3).
a(n+2) = a(n)+9 (n>2), a(2n+1) = a(2n)+4 (n>1), a(2n) = a(2n-1)+5 (n>1). (End)
Sum_{n>=3} (-1)^(n+1)/a(n) = cot(2*Pi/9)*Pi/9. - Amiram Eldar, Jan 12 2024
MATHEMATICA
Join[{-1}, Table[9*n/2 + (-1)^n/4 - 45/4, {n, 3, 60}]] (* Amiram Eldar, Jan 12 2024 *)
CROSSREFS
Cf. A063232, A063233, A017185 (bisection).
Sequence in context: A174008 A140491 A122823 * A287726 A190518 A190750
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Jul 14 2001
STATUS
approved