OFFSET
1,2
COMMENTS
This sequence is a decimal variant of A238757.
This sequence is a self-inverse permutation of the natural numbers.
LINKS
EXAMPLE
The first terms, alongside n + a(n), are:
n a(n) n+a(n)
-- ---- ------
1 1 2
2 2 4
3 3 6
4 4 8
5 10 15
6 11 17
7 12 19
8 20 28
9 30 39
10 5 15
11 6 17
12 7 19
13 13 26
14 14 28
15 21 36
PROG
(PARI) s=0; for (n=1, 64, for (v=1, oo, if (!bittest(s, v) && sumdigits(n+v)==sumdigits(n)+sumdigits(v), print1(v", "); s+=2^v; break)))
CROSSREFS
KEYWORD
AUTHOR
Rémy Sigrist, Jul 11 2020
STATUS
approved