cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A129195 a(n) = denominator(n!/4^n).

Original entry on oeis.org

1, 4, 8, 32, 32, 128, 256, 1024, 512, 2048, 4096, 16384, 16384, 65536, 131072, 524288, 131072, 524288, 1048576, 4194304, 4194304, 16777216, 33554432, 134217728, 67108864, 268435456, 536870912, 2147483648, 2147483648, 8589934592, 17179869184, 68719476736
Offset: 0

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Author

Paul Barry, Apr 02 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Denominator[n!/4^n],{n,0,30}] (* Harvey P. Dale, Mar 05 2013 *)

Formula

a(n) = denominator((1/(2*Pi))*int(exp(i*4*t)(-((Pi-t)/i)^n),t,0,2*Pi)), i=sqrt(-1).
a(n) = 2^A092391(n).