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A317441
a(n) = number of k with 1 <= k <= n-1 such that a(k) and a(n-k) have the same binary length (A070939).
2
0, 1, 2, 1, 2, 3, 0, 5, 4, 1, 6, 3, 0, 5, 4, 1, 10, 5, 2, 7, 0, 7, 10, 5, 6, 7, 2, 5, 8, 5, 8, 7, 10, 9, 6, 7, 8, 7, 10, 11, 6, 7, 8, 11, 6, 17, 8, 9, 8, 19, 8, 13, 10, 15, 6, 19, 10, 9, 6, 19, 8, 13, 14, 13, 10, 17, 14, 15, 10, 19, 14, 9, 16, 15, 10, 11, 20
OFFSET
1,3
COMMENTS
See A317420 for similar sequences.
EXAMPLE
For n = 4:
- A070939(a(1)) = 1 <> 2 = A070939(a(3)),
- A070939(a(2)) = 1 = 1 = A070939(a(2)),
- A070939(a(3)) = 2 <> 1 = A070939(a(1)),
- hence a(4) = 1.
PROG
(PARI) l = vector(77); for (n=1, #l, l[n] = #binary(max(1, v=sum(k=1, n-1, l[k]==l[n-k]))); print1 (v ", "))
CROSSREFS
Sequence in context: A082501 A249858 A249857 * A249777 A289065 A132815
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Jul 28 2018
STATUS
approved