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Search: id:A133101
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| A133101 |
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Expansion of f(x^2, x^3) in powers of x where f() is Ramanujan's two variable theta function. |
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+0
1
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| 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list; graph; listen)
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OFFSET
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0,1
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LINKS
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Index entries for characteristic functions
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FORMULA
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The characteristic function of A057569.
Euler transform of period 10 sequence [ 0, 1, 1, -1, -1, -1, 1, 1, 0, -1, ...].
G.f.: Prod_{k>0} (1-x^(5k)) * (1+x^(5k-2)) * (1+x^(5k-3)) = Sum_{k} x^((5*k^2 + k) / 2).
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EXAMPLE
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1 + q^2 + q^3 + q^9 + q^11 + q^21 + q^24 + q^38 + q^42 + q^60 + q^65 + ...
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PROGRAM
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(PARI) {a(n) = if( n<0, 0, polcoeff( prod(k=1, n, 1 + x^k*[ -1, 0, 1, 1, 0][k%5+1], 1+x*O(x^n)), n))}
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CROSSREFS
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|A113428(n)| = a(n).
Sequence in context: A071039 A074332 A113428 this_sequence A068426 A138709 A082960
Adjacent sequences: A133098 A133099 A133100 this_sequence A133102 A133103 A133104
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KEYWORD
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nonn
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AUTHOR
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Michael Somos, Sep 11 2007
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