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A135070
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a(n) = [x^(2^n+n-2)] (x + x^2 + x^4 +...+ x^(2^n))^n for n>=2.
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4
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1, 3, 18, 70, 600, 4956, 52528, 358128, 6654600, 79967800, 1453049400, 16239408120, 392541718660, 5252687631660, 108961629396480, 1395025456201408, 62831427044385384, 1223872353413404344
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,2
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FORMULA
| n(n-1)/2 divides a(n): A135071(n) = a(n)/[n(n-1)/2] for n>=2.
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PROG
| (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))}
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CROSSREFS
| Cf. A135068, A135069, A135071.
Sequence in context: A098522 A174764 A114633 * A073961 A152897 A059393
Adjacent sequences: A135067 A135068 A135069 * A135071 A135072 A135073
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KEYWORD
| nonn
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AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), Nov 17 2007
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EXTENSIONS
| a(15) - a(19) from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Apr 29 2009
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