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A135070 a(n) = [x^(2^n+n-2)] (x + x^2 + x^4 + x^8 + ... + x^(2^n))^n for n>=2. 4
1, 3, 18, 70, 600, 4956, 52528, 358128, 6654600, 79967800, 1453049400, 16239408120, 392541718660, 5252687631660, 108961629396480, 1395025456201408, 62831427044385384, 1223872353413404344 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,2
LINKS
FORMULA
n(n-1)/2 divides a(n): A135071(n) = a(n)/[n(n-1)/2] for n>=2.
MATHEMATICA
f[x_, n_] := (Sum[x^(2^k), {k, 0, n}])^n; Table[Coefficient[f[x, n], x^(2^n + n - 2)] , {n, 2, 10}] (* G. C. Greubel, Sep 22 2016 *)
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))}
CROSSREFS
Sequence in context: A098522 A174764 A114633 * A073961 A305623 A280804
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 17 2007
EXTENSIONS
a(15) - a(19) from Alois P. Heinz, Apr 29 2009
STATUS
approved

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Last modified March 28 08:02 EDT 2024. Contains 371236 sequences. (Running on oeis4.)