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Search: id:A123631
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| A123631 |
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Expansion of q/(chi(-q)*chi(-q^11))^2 in powers of q where chi() is a Ramanujan theta function. |
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+0
1
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| 1, 2, 3, 6, 9, 14, 22, 32, 46, 66, 93, 130, 180, 244, 331, 444, 590, 780, 1024, 1334, 1730, 2234, 2867, 3664, 4660, 5904, 7449, 9364, 11728, 14638, 18211, 22584, 27927, 34436, 42342, 51924, 63523, 77512, 94364, 114624, 138920, 168012, 202786, 244270
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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Euler transform of period 22 sequence [ 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 4, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, ...].
G.f. A(x) satisfies 0=f(A(x), A(x^2)) where f(u, v)= u^2 -v -u*v*(4 +4*v).
G.f. A(x) satisfies 0= f(A(x), A(x^3)) where f(u, v)= (u^2+ v^2)^2 -u*v* (1+ 3*(u+v) +4*u*v)^2.
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PROGRAM
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(PARI) {a(n)=local(A); if(n<1, 0, n--; A=x*O(x^n); polcoeff( (eta(x^2+A)*eta(x^22+A)/ eta(x+A)/eta(x^11+A))^2, n))}
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CROSSREFS
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Adjacent sequences: A123628 A123629 A123630 this_sequence A123632 A123633 A123634
Sequence in context: A128518 A022567 A134004 this_sequence A018060 A115856 A032231
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KEYWORD
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nonn
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AUTHOR
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Michael Somos, Oct 03 2006
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