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A132130 McKay-Thompson series of class 10D for the Monster group with a(0) = 6. 1
1, 6, 21, 62, 162, 378, 819, 1680, 3276, 6138, 11145, 19662, 33840, 57048, 94362, 153432, 245757, 388218, 605466, 933414, 1423614, 2149586, 3215844, 4769544, 7016572, 10243896, 14848809, 21378276, 30582360, 43484304, 61473438, 86428896 (list; graph; refs; listen; history; internal format)
OFFSET

-1,2

COMMENTS

Ramanujan theta functions: f(q) := Prod_{k>=1} (1-(-q)^k) (see A121373), phi(q) := theta_3(q) := Sum_{k=-oo..oo} q^(k^2) (A000122), psi(q) := Sum_{k=0..oo} q^(k*(k+1)/2) (A10054), chi(q) := Prod_{k>=0} (1+q^(2k+1)) (A000700).

LINKS

M. Somos, Introduction to Ramanujan theta functions

Eric Weisstein's World of Mathematics, Ramanujan Theta Functions

Index entries for McKay-Thompson series for Monster simple group

FORMULA

Euler transform of period 10 sequence [ 6, 0, 6, 0, 0, 0, 6, 0, 6, 0, ...].

G.f. A(x) satisfies 0= f(A(x), A(x^2), A(x^4)) where f(u, v, w)= (v -u^2)*(v -w^2) -u*w* (12*(1+v^2) -20*v).

G.f. is Fourier series of a weight 0 level 10 modular form. f(-1/ ( 10 t)) = f(t) where q = exp(2 pi i t).

G.f.: x^(-1)* (Product_{k>0} (1+x^k)/ (1+x^(5*k)))^6.

G.f.: 1 / ( x * Product_{k>0} P(10,x^k)^6 ) where P(n,x) is the n-th cyclotomic polynomial.

Expansion of q^(-1) * (chi(-q^5) / chi(-q))^6 in powers of q where chi() is a Ramanujan theta function.

Expansion of (eta(q^2) * eta(q^5) / (eta(q) * eta(q^10)))^6 in powers of q.

EXAMPLE

1/q + 6 + 21*q + 62*q^2 + 162*q^3 + 378*q^4 + 819*q^5 + 1680*q^6 + ...

PROG

(PARI) {a(n)= local(A); if(n<-1, 0, n++; A= x*O(x^n); polcoeff( (eta(x^2+A)* eta(x^5+A)/ eta(x+A)/ eta(x^10+A))^6, n))}

CROSSREFS

A058100(n)= a(n) unless n=0.

Sequence in context: A012593 A048476 A122678 * A022571 A117962 A105457

Adjacent sequences:  A132127 A132128 A132129 * A132131 A132132 A132133

KEYWORD

nonn

AUTHOR

Michael Somos, Aug 11 2007, Aug 09 2008

EXTENSIONS

Edited by N. J. A. Sloane (njas(AT)research.att.com), May 16 2008 at the suggestion of R. J. Mathar

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Last modified February 17 13:28 EST 2012. Contains 206031 sequences.