OFFSET
1,2
COMMENTS
This sequence is inspired by Ulam sequence (A002858).
All terms belong to A007931.
Applying the mapping 1 -> 0, 2 -> 1 to the decimal representations of the terms of this sequence gives the sequence U({0, 1}) described in the article by Bade et al. in Links section. - Rémy Sigrist, Aug 08 2020
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..15616 (terms < 10^15)
Tej Bade, Kelly Cui, Antoine Labelle, and Deyuan Li, Ulam Sets in New Settings, arXiv:2008.02762 [math.CO], 2020. See also Integers (2020) Vol. 20, #A102.
Rémy Sigrist, PARI program for A336528
EXAMPLE
The first terms, alongside A007931 and the corresponding concatenations, are:
n a(n) A007931 concatenations
-- ---- ------- --------------
1 1 1
2 2 2
11
3 12 12 1|2
4 21 21 2|1
22
111 1|11, 11|1
5 112 112 1|12
121 1|21, 12|1
6 122 122 12|2
7 211 211 21|1
212 2|12, 21|2
8 221 221 2|21
222
1111
9 1112 1112 1|112
10 1121 1121 112|1
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Jul 24 2020
STATUS
approved