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Search: id:A093831
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| A093831 |
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Expansion of (eta(q^2)eta(q^10)/(eta(q)eta(q^5)))^4 in powers of q. |
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+0
1
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| 1, 4, 10, 24, 51, 104, 206, 384, 697, 1228, 2112, 3568, 5898, 9592, 15358, 24256, 37850, 58340, 88980, 134344, 200972, 298112, 438538, 640256, 928041, 1336104, 1911436, 2717776, 3842110, 5401784, 7555012, 10514176, 14562432, 20077672
(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 10 sequence [ 4, 0, 4, 0, 8, 0, 4, 0, 4, 0, ...].
G.f. A(x) satisfies 0=f(A(x), A(x^2)) where f(u, v)= u^2 -v*(1+8*u+16*u*v)
G.f.: x/(Product_{k>0} (1-x^(10k-5))(1-x^(2k-1)))^4.
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PROGRAM
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(PARI) a(n)=if(n<1, 0, n--; polcoeff((1/prod(k=1, (n+5)\10, 1-x^(10*k-5), 1+x*O(x^n))/prod(k=1, (n+1)\2, 1-x^(2*k-1), 1+x*O(x^n)))^4, n))
(PARI) {a(n)=local(A); if(n<1, 0, n--; A=x*O(x^n); polcoeff( (eta(x^2+A)*eta(x^10+A)/eta(x+A)/eta(x^5+A))^4, n))}
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CROSSREFS
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Sequence in context: A001979 A128516 A022569 this_sequence A052365 A107659 A162588
Adjacent sequences: A093828 A093829 A093830 this_sequence A093832 A093833 A093834
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KEYWORD
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nonn
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AUTHOR
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Michael Somos, Apr 17 2004, Oct 04 2004
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com) at the suggestion of Andrew Plewe, Jun 05 2007
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