A161395 a(n) = (n+1)*A000521(n)/24.

0, 31, 16407, 2686720, 144049995, 4217886720, 83300660150, 1240173462528, 14885664690645, 150559082496000, 1323516762410175, 10343388600230400, 73105955749759647, 473586598163128320, 2842005898548916470

Offset

-1,2

Comments

Comment from John McKay (mckay(AT)encs.concordia.ca), Jun 09 2009: This is in a paper by Lehmer from about 1945. It is related to the q-coefficients of j'/j. Added Oct 13 2010: Note j'/j = weight 2 on the modular group = E6/E4 = (1-504...)/(1+240...) = -1/1 mod 24 so j'+j == 0 (mod 24) so coefficient of q^n gives n*c(n) + c(n) = (n+1)c(n) == 0 (mod 24).

Links

G. C. Greubel, Table of n, a(n) for n = -1..1000

Formula

a(n) ~ exp(4*Pi*sqrt(n)) * n^(1/4) / (3 * 2^(7/2)). - Vaclav Kotesovec, Jun 09 2018

Mathematica

a[n_] := With[{tau = Log[q]/(2 Pi I)}, SeriesCoefficient[Series[1728 KleinInvariantJ[tau], {q, 0, n}], {q, 0, n}]]; Table[(n + 1) a[n]/24, {n, -1, 100}] (* G. C. Greubel, Feb 20 2017 *)

Crossrefs

Sequence in context: A073099 A245571 A074218 * A215610 A292009 A086122

Adjacent sequences: A161392 A161393 A161394 * A161396 A161397 A161398

Keyword

nonn

Author

Alexander R. Povolotsky, Jun 09 2009

Status

approved