OFFSET
2,1
COMMENTS
Also the number of distinct words which can be formed from (123..n)* by taking every 4^k-th term from some initial index i, with i and k nonnegative. (Follows from Case 2 of Theorem 2.1) - Charlie Neder, Feb 28 2019
LINKS
Charlie Neder, Table of n, a(n) for n = 2..128
Klaus Sutner and Sam Tetruashvili, Inferring Automatic Sequences.
FORMULA
a(n) <= A217519(n). In particular, it appears that a(n) = A217519(n)/2 whenever this result is an integer, and a(n) = A217519(n) for n = 2, 7, 14, 23, 31, 46, 47, 49, 62, 71, 89, 94, 98... - Charlie Neder, Feb 28 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 07 2012
EXTENSIONS
a(11)-a(20) added (see Inferring Automatic Sequences) by Vincenzo Librandi, Nov 18 2012
a(21)-a(54) from Charlie Neder, Feb 28 2019
STATUS
approved