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Search: id:A124863
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| A124863 |
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Expansion of q^(-1/2)(kk')/4 in powers of q where k is the Jacobian elliptic modulus, k' the complementary modulus and q is the nome. |
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+0
1
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| 1, -12, 78, -376, 1509, -5316, 16966, -50088, 138738, -364284, 913824, -2203368, 5130999, -11585208, 25444278, -54504160, 114133296, -234091152, 471062830, -931388232, 1811754522, -3471186596, 6556994502, -12222818640, 22502406793
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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Expansion of 1/chi(q)^12 in powers of q where chi() is a Ramanujan theta function.
Expansion of q^(-1/2)(eta(q)eta(q^4)/eta(q^2)^2)^12 in powers of q.
Euler transform of period 4 sequence [ -12, 12, -12, 0, ...].
G.f.: Prod_{k>0} (1+(-x)^k)^12.
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PROGRAM
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(PARI) {a(n)=local(A); if(n<0, 0, A=x*O(x^n); polcoeff( (eta(x+A)*eta(x^4+A)/eta(x^2+A)^2)^12, n))}
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CROSSREFS
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Cf. a(n)=(-1)^n*A022577(n). Convolution square is A100130.
Sequence in context: A008494 A001288 A121665 this_sequence A022577 A030116 A035042
Adjacent sequences: A124860 A124861 A124862 this_sequence A124864 A124865 A124866
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KEYWORD
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sign
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AUTHOR
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Michael Somos, Nov 10 2006
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