The terms a(0)-a(4) are from the b-file for A002858. The remaining terms are from the paper by Philip Gibbs. As the sequence settles, its terms lie very close to the straight line 13.51*n.
Table of n, a(n) for n=0..9.
Philip Gibbs, An Efficient Method for Computing Ulam Numbers, viXra:1508.0085 (2015).
Wikipedia, Ulam number.
a(n) = A002858(10^n).
Sequence in context: A041612 A046674 A073421 * A295439 A159873 A259458
Adjacent sequences: A346213 A346214 A346215 * A346217 A346218 A346219
Frank M Jackson, Oct 16 2021
a(5)-a(9) from Philip Gibbs and Jud McCranie, Feb 29 2012 - Sep 09 2015