OFFSET
1,2
COMMENTS
Apparently every positive integer appears in the sequence.
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10000
Rémy Sigrist, Scatterplot of (n, a(n)) for n = 1..10000000
FORMULA
a(n) = (3*a(2*n) - a(2*n+1)) / 2.
EXAMPLE
The first terms, alongside k(n) and associate children, are:
n a(n) k(n) a(2*n) a(2*n+1)
-- ---- ---- ------ --------
1 1 1 2 4
2 2 1 3 5
3 4 2 6 10
4 3 4 7 15
5 5 3 8 14
6 6 5 11 21
7 10 2 12 16
8 7 2 9 13
9 15 3 18 24
10 8 9 17 35
PROG
(PARI) lista(nn) = my (a=[1], s=2^a[1]); for (n=1, ceil(nn/2), for (k=1, oo, if (!bittest(s, a[n]+k) && !bittest(s, a[n]+3*k), a=concat(a, [a[n]+k
, a[n]+3*k]); s+=2^(a[n]+k) + 2^(a[n]+3*k); break))); a[1..nn]
CROSSREFS
KEYWORD
AUTHOR
Rémy Sigrist, Dec 16 2018
STATUS
approved