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Search: id:A135071
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| A135071 |
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a(n) = [x^(2^n+n-2)] (x + x^2 + x^4 +...+ x^(2^n))^n /(n*(n-1)/2)) for n>=2. |
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+0
4
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| 1, 1, 3, 7, 40, 236, 1876, 9948, 147880, 1453960, 22015900, 208197540, 4313645260
(list; graph; listen)
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OFFSET
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2,3
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FORMULA
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a(n) = A135070(n)/[n(n-1)/2] for n>=2.
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PROGRAM
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(PARI) {a(n)=if(n<2, 0, polcoeff(sum(j=0, n, x^(2^j)+O(x^(2^n+n)))^n, 2^n+n-2)/(n*(n-1)/2))}
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CROSSREFS
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Cf. A135068, A135069, A135070.
Adjacent sequences: A135068 A135069 A135070 this_sequence A135072 A135073 A135074
Sequence in context: A018942 A018943 A019024 this_sequence A096219 A128647 A071730
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KEYWORD
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more,nonn,easy
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Nov 17 2007
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