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.

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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).
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