A-Sequence

Author

Eric W. Weisstein
July 8, 2003

This notebook downloaded from http://mathworld.wolfram.com/notebooks/IntegerSequences/A-Sequence.nb.

For more information, see Eric's MathWorld entry http://mathworld.wolfram.com/A-Sequence.html.

©2005 Wolfram Research, Inc. except for portions noted otherwise

Definition

x[1]:=1
x[i_]:=x[i]=Max[Table[(j+1)(i-x[j]),{j,i-1}]]

Table[x[n],{n,20}]

Reciprocal Sum

N[Plus@@(1/Table[x[n],{n,5000}]),20]//Timing

N[Plus@@(1/Table[x[n],{n,10000}]),20]//Timing

N[Plus@@(1/Table[x[n],{n,20000}]),20]//Timing

N[Plus@@(1/Table[x[n],{n,50000}]),20]//Timing