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Search: id:A131797
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| A131797 |
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Expansion of eta(q)* eta(q^15)/ (eta(q^6)* eta(q^10)) in powers of q. |
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3
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| 1, -1, -1, 0, 0, 1, 1, 0, -1, 0, 1, 0, 0, -1, -2, -1, 2, 3, 1, -1, -2, -3, 0, 3, 1, -2, -2, 0, 2, 6, 3, -4, -7, -3, 2, 5, 6, -2, -8, -3, 5, 6, 2, -4, -12, -7, 10, 15, 6, -5, -13, -12, 4, 18, 7, -11, -14, -6, 10, 24, 14, -20, -32, -12, 12, 29, 24, -9, -36, -15, 22, 30, 13, -22, -50, -27, 36, 63, 26, -24, -56, -45, 22, 69, 30, -42, -62
(list; graph; listen)
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OFFSET
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0,15
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FORMULA
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Euler transform of period 30 sequence [ -1, -1, -1, -1, -1, 0, -1, -1, -1, 0, -1, 0, -1, -1, -2, -1, -1, 0, -1, 0, -1, -1, -1, 0, -1, -1, -1, -1, -1, 0, ...].
G.f. A(x) satisfies 0= f(A(x), A(x^2)) where f(u,v)= v*(u^2-v) -2*u*(u-1).
G.f.: Product_{k>0} (1-x^k)* (1-x^(15*k))/ ((1-x^(6*k))* (1-x^(10*k))).
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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^15+A)/ eta(x^6+A)/ eta(x^10+A), n))}
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CROSSREFS
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A131794(n)= -a(n) unless n=0, A131796(n)= -a(n) unless n=0.
Sequence in context: A124448 A138243 A131796 this_sequence A131794 A133674 A098666
Adjacent sequences: A131794 A131795 A131796 this_sequence A131798 A131799 A131800
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KEYWORD
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sign
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AUTHOR
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Michael Somos, Jul 16 2007
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