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A115977 Expansion of elliptic modular function lambda in powers of the nome q. +0
2
16, -128, 704, -3072, 11488, -38400, 117632, -335872, 904784, -2320128, 5702208, -13504512, 30952544, -68901888, 149403264, -316342272, 655445792, -1331327616, 2655115712, -5206288384, 10049485312, -19115905536, 35867019904, -66437873664 (list; graph; listen)
OFFSET

1,1

COMMENT

Expansion of Jacobi elliptic m=k^2 in powers of the nome q.

REFERENCES

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math.Series 55, Tenth Printing, December 1972, p. 591.

J. M. Borwein and P. B. Borwein, Pi and the AGM, Wiley, 1987, p. 121.

A. Erdelyi, Higher Transcendental Functions, McGraw-Hill, 1955, Vol. 3, p. 23.

LINKS

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, December 1972 [alternative scanned copy].

Eric Weisstein's World of Mathematics, Elliptic Lambda Function

FORMULA

G.f. A(x) satisfies 0=f(A(x),A(x^2)) where f(u,v)=u^2(1-v)^2 -16v(1-u).

G.f.: 16q*(Product_{k>0} (1+q^(2k))/(1+q^(2k-1)))^8 = (theta_2(q)/theta_3(q))^4.

PROGRAM

(PARI) {a(n)=local(A); if(n<1, 0, n--; A=x*O(x^n); 16*polcoeff( (eta(x+A)*eta(x^4+A)^2/eta(x^2+A)^3)^8, n))}

CROSSREFS

a(n)=16*A005798(n). a(n)=-(-1)^n*A014972(n) if n>0.

Sequence in context: A045651 A035473 A014972 this_sequence A128692 A132136 A067488

Adjacent sequences: A115974 A115975 A115976 this_sequence A115978 A115979 A115980

KEYWORD

sign

AUTHOR

Michael Somos, Feb 09 2006

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Last modified November 18 20:14 EST 2008. Contains 147244 sequences.


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