A182005 Let s(n) = s_3(n) be digit sum of n in base 3. Consider iterations: a_1(n) = s(2^n), a_2(n) = s(2^n+a_1(n)),a_3(n)=s(2^n+a_2(n)),...The sequence lists those n for which these iterations are (eventually) periodic with period > 1.

5, 7, 8, 17, 21, 23, 26, 31, 39, 40, 41, 45, 49, 51, 52, 53, 58, 62, 64, 67, 69, 78, 81, 82, 84, 87, 91, 93, 108, 113, 115, 116, 119, 121, 122, 128, 131, 135, 136, 139, 142, 151, 152, 155, 163, 170, 173, 174, 178, 181, 191, 193, 195, 198, 201

Offset: 1

Author

Vladimir Shevelev and Peter J. C. Moses, Apr 06 2012

Keywords

• nonn
• base

Comments

For every number n which is not in the sequences, there exists N=N(n) such that, for k>N, a_k(n)=constant(k).

Crossrefs

Cf. A053735, A000079.

Formula

Enlarged on 1 numbers which are not in A169655.