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.

A329496 Denominator of second moment of the n-th term of Ulam's "history-dependent random sequence".

Original entry on oeis.org

1, 1, 2, 3, 8, 60, 240, 2520, 40320, 181440, 725760, 266112, 95800320, 17791488, 1585059840, 130767436800, 1394852659200, 35568742809600, 20324995891200, 12164510040883200, 69511485947904000, 5109094217170944000, 32114306507931648000
Offset: 1

Views

Author

N. J. A. Sloane, Nov 17 2019

Keywords

Examples

			1, 4, 25/2, 101/3, 655/8, 11077/60, 94199/240, 2005319/2520, ...
		

Crossrefs

Programs

  • Maple
    s:=[1]; a:=[0];
    for N from 2 to 40 do # N = n+1
    n:=N-1;
    t1:=s[n]+(1/n)*add(s[k],k=1..n)+2*s[n]/n+(2/n)*a[n];
    t2:=s[n]+(1/n)*add(s[k],k=1..n)+a[n]+(2/n)*add(a[k],k=1..n);
    s:=[op(s),t1];
    a:=[op(a),t2];
    od:
    s; # sigma_n
    a; # alpha_n
    sn:=map(numer,s); # A329495
    sd:=map(denom,s); # A329496
    an:=map(numer,a); # A329497
    ad:=map(denom,a); # A329498