cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A212301 Coefficients of the twisted K3 elliptic genus attached to the conjugacy class 1A in the Mathieu group M_24.

Original entry on oeis.org

-2, 90, 462, 1540, 4554, 11592, 27830, 61686, 131100, 265650, 521136, 988770, 1830248, 3303630, 5844762, 10139734, 17301060, 29051484, 48106430, 78599556, 126894174, 202537080, 319927608, 500376870, 775492564, 1191453912, 1815754710, 2745870180, 4122417420, 6146311620
Offset: 0

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Author

Charles R Greathouse IV and John F. R. Duncan, Jun 16 2012

Keywords

Comments

This is the "right" normalization of A169717.

Crossrefs

Programs

  • PARI
    E2(q,prec)=1-24*sum(k=1,prec,k*q^k/(1-q^k))
    F22(q,prec)=sum(s=1,min(prec-1,sqrt(2*prec)-1/2),my(t=0);forstep(r=s+1,2*prec\s,2,t+=(-1)^r*q^(r*s/2));s*t)
    list(lim)=my(q='q+O('q^lim));Vec((-2*E2(q,lim)+48*F22(q,lim))/eta(q)^3)

Formula

a(n) = 2*A169717(n).