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.

A131045 Binomial transform of Euler's totient function phi(n+1).

Original entry on oeis.org

1, 2, 5, 12, 29, 68, 155, 348, 775, 1712, 3745, 8112, 17431, 37252, 79355, 168710, 358037, 758020, 1599675, 3362876, 7041593, 14692956, 30577435, 63531092, 131901879, 273804738, 568366037, 1179585610, 2446603047, 5068970880
Offset: 0

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Author

Gary W. Adamson, Jun 11 2007

Keywords

Examples

			a(3) = (1,3,3,1) dot (1,1,2,2) = 1 + 3 + 6 + 2 = 12.
		

Crossrefs

Programs

  • Maple
    with(numtheory); a := proc (n) options operator, arrow; sum(binomial(n, j)*phi(j+1), j = 0 .. n) end proc; seq(a(n), n = 0 .. 30); # Emeric Deutsch, Jul 09 2007
  • Mathematica
    Table[Sum[Binomial[n,k]*EulerPhi[k+1], {k, 0, n}], {n, 0, 30}] (* Vaclav Kotesovec, Oct 30 2017 *)
  • PARI
    a(n) = sum(j=0, n, binomial(n,j)*eulerphi(j+1)); \\ Michel Marcus, Feb 26 2019

Formula

a(n) = Sum_{j=0..n} binomial(n,j)*phi(j+1). - Emeric Deutsch, Jul 09 2007

Extensions

More terms from Emeric Deutsch, Jul 09 2007