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A058675 McKay-Thompson series of class 42a for Monster. 2
1, 0, 3, 3, 3, 6, 7, 6, 12, 16, 18, 24, 33, 33, 48, 57, 69, 87, 106, 117, 153, 181, 207, 258, 307, 345, 429, 496, 570, 681, 805, 906, 1083, 1252, 1425, 1671, 1934, 2190, 2562, 2929, 3327, 3840, 4400, 4953, 5727, 6500, 7335, 8388, 9521, 10686, 12198, 13775 (list; graph; refs; listen; history; text; internal format)
OFFSET

-1,3

LINKS

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

D. Ford, J. McKay and S. P. Norton, More on replicable functions, Comm. Algebra 22, No. 13, 5175-5193 (1994).

Index entries for McKay-Thompson series for Monster simple group

FORMULA

a(n) ~ exp(2*Pi*sqrt(2*n/21)) / (2^(3/4) * 21^(1/4) * n^(3/4)). - Vaclav Kotesovec, May 30 2018

Expansion of A - q/A, where A = q^(1/2)*(eta(q^3)*eta(q^7)/(eta(q)* eta(q^21))), in powers of q. - G. C. Greubel, Jun 19 2018

EXAMPLE

T42a = 1/q + 3*q^3 + 3*q^5 + 3*q^7 + 6*q^9 + 7*q^11 + 6*q^13 + 12*q^15 + ...

MATHEMATICA

CoefficientList[Series[(QPochhammer[x^3]^2 * QPochhammer[x^7]^2 - x*QPochhammer[x]^2 * QPochhammer[x^21]^2) / (QPochhammer[x] * QPochhammer[x^3] * QPochhammer[x^7] * QPochhammer[x^21]), {x, 0, 100}], x] (* Vaclav Kotesovec, May 30 2018 *)

eta[q_]:= q^(1/24)*QPochhammer[q]; A:= q^(1/2)*(eta[q^3]*eta[q^7]/( eta[q]*eta[q^21])); a:= CoefficientList[Series[A - q/A, {q, 0, 60}], q]; Table[a[[n]], {n, 0, 50}] (* G. C. Greubel, Jun 19 2018 *)

PROG

(PARI) q='q+O('q^50); A = (eta(q^3)*eta(q^7)/(eta(q)* eta(q^21))); Vec(A - q/A) \\ G. C. Greubel, Jun 19 2018

CROSSREFS

Cf. A000521, A007240, A014708, A007241, A007267, A045478, etc.

Sequence in context: A219299 A219595 A219173 * A025497 A031502 A153004

Adjacent sequences:  A058672 A058673 A058674 * A058676 A058677 A058678

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Nov 27 2000

EXTENSIONS

More terms from Vaclav Kotesovec, May 30 2018

STATUS

approved

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Last modified January 16 21:37 EST 2019. Contains 319206 sequences. (Running on oeis4.)