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A361676
a(n) is the greatest k such that n appears in the k-th row of triangle A361644.
4
0, 1, 2, 3, 5, 5, 6, 7, 11, 10, 10, 11, 13, 13, 14, 15, 23, 22, 21, 21, 21, 21, 22, 23, 27, 26, 26, 27, 29, 29, 30, 31, 47, 46, 45, 45, 43, 42, 42, 43, 43, 42, 42, 43, 45, 45, 46, 47, 55, 54, 53, 53, 53, 53, 54, 55, 59, 58, 58, 59, 61, 61, 62, 63, 95, 94, 93
OFFSET
0,3
COMMENTS
All terms belong to A003754.
To compute a(n): consider the run lengths in the binary expansion of n (i.e. the n-th row of A101211) and replace from left to right each value v > 1 at even index with (1, v-1); at the end, there remain the run lengths in the binary expansion of a(n).
See A361645 for the least k's.
FORMULA
a(n) >= n with equality iff n belongs to A003754.
a(n) >= A361645(n) with equality iff n belongs to A000975.
EXAMPLE
The first terms, in decimal and in binary, are:
n a(n) bin(n) bin(a(n))
-- ---- ------ ---------
0 0 0 0
1 1 1 1
2 2 10 10
3 3 11 11
4 5 100 101
5 5 101 101
6 6 110 110
7 7 111 111
8 11 1000 1011
9 10 1001 1010
10 10 1010 1010
11 11 1011 1011
12 13 1100 1101
13 13 1101 1101
14 14 1110 1110
15 15 1111 1111
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Mar 20 2023
STATUS
approved