1,1

There is a slight ambiguity in the definition, but I believe these are all the numbers which eventually return to themselves under iteration of k -> A169639(k). - N. J. A. Sloane, Jun 11 2021

Table of n, a(n) for n=1..20.

Sequence in context: A268790 A077786 A188537 * A255786 A147028 A105988

Adjacent sequences: A169638 A169639 A169640 * A169642 A169643 A169644

nonn,word

Jacques ALARDET, Apr 04 2010

Edited by N. J. A. Sloane, Apr 05 2010

approved