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A006352 Coefficients in expansion of Eisenstein series E_2 (also called E_1 or G_2).
(Formerly M5145)
+0
16
1, -24, -72, -96, -168, -144, -288, -192, -360, -312, -432, -288, -672, -336, -576, -576, -744, -432, -936, -480, -1008, -768, -864, -576, -1440, -744, -1008, -960, -1344, -720, -1728, -768, -1512, -1152, -1296, -1152, -2184, -912, -1440, -1344, -2160, -1008, -2304, -1056, -2016, -1872, -1728 (list; graph; listen)
OFFSET

0,2

COMMENT

Expansion of Ramanujan's function P(q).

REFERENCES

F. Beukers, Another congruence for the Apery numbers. J. Number Theory 25 (1987), no. 2, 201-210.

R. C. Gunning, Lectures on Modular Forms. Princeton Univ. Press, Princeton, NJ, 1962, p. 53.

N. Koblitz, Introduction to Elliptic Curves and Modular Forms, Springer-Verlag, 1984, see pp. 111 and 113.

LINKS

T. D. Noe, Table of n, a(n) for n=0..1000

H. Ochiai, Counting functions for branched covers of elliptic curves and quasi-modular forms

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Index entries for sequences related to Eisenstein series

FORMULA

n-th term is -24*sigma(n), for n>0.

G.f. A(x) satisfies 0=f(A(x), A(x^2), A(x^3), A(x^6)) where f(u1, u2, u3, u6)=u1^2+4*u2^2+9*u3^2+36*u6^2-8*u1*u2+6*u1*u3+24*u2*u6-72*u3*u6 . - Michael Somos May 29 2005

G.f.: 1-24(Sum_{k>0} kx^k/(1-x^k)).

MAPLE

E := proc(k) local n, t1; t1 := 1-(2*k/bernoulli(k))*add(sigma[k-1](n)*q^n, n=1..60); series(t1, q, 60); end; E(2);

PROGRAM

(PARI) a(n)=if(n<1, n==0, -24*sigma(n))

CROSSREFS

Cf. A006352 (E_2), A004009 (E_4), A013973 (E_6), A008410 (E_8), A013974 (E_10), A029828 (E_12), A058550 (E_14), A029829 (E_16), A029830 (E_20), A029831 (E_24).

Sequence in context: A069174 A124717 A126378 this_sequence A090860 A064200 A042128

Adjacent sequences: A006349 A006350 A006351 this_sequence A006353 A006354 A006355

KEYWORD

sign,easy,nice

AUTHOR

njas

EXTENSIONS

More terms from Erich Friedman (erich.friedman(AT)stetson.edu).

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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