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.

Showing 1-2 of 2 results.

A167368 a(n) = sigma((n!!)!).

Original entry on oeis.org

1, 1, 3, 12, 159120, 6686252969760, 89050715142739003008099466232718435351438398888454549774336000
Offset: 0

Views

Author

Vladimir Joseph Stephan Orlovsky, Nov 01 2009

Keywords

Crossrefs

Cf. A062569, A167367.

Programs

  • Mathematica
    Array[DivisorSigma[1,#!!! ]&,7,1]
  • PARI
    A167368(n)=sigma( prod(k=0,n\2-1,n-2*k) ! )  \\ M. F. Hasler, Feb 07 2011

Formula

a(n) = A000203(A161563(n)).

Extensions

a(0)=1 prepended by Alois P. Heinz, Jan 12 2022

A167369 sigma(n!,n!).

Original entry on oeis.org

1, 5, 47450, 1333735856351858432985890996140258
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Nov 01 2009

Keywords

Crossrefs

Cf. A062569, A167367, A167368

Programs

  • Mathematica
    Array[DivisorSigma[ #!,#! ]&,5,1]
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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