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A308638
a(n) is the number of k > 0 such that n-1-2*k > 0 and the points (n-1-2*k, a(n-1-2*k)), (n-1-k, a(n-1-k)) and (n-1, a(n-1)) are aligned.
7
0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 2, 3, 1, 1, 1, 1, 3, 0, 1, 2, 3, 1, 4, 2, 1, 3, 2, 4, 1, 1, 2, 2, 2, 3, 3, 4, 2, 3, 3, 2, 4, 4, 0, 1, 3, 2, 1, 3, 4, 5, 3, 6, 5, 3, 2, 6, 0, 3, 6, 4, 0, 3, 5, 5, 5, 4, 3, 6, 3, 3, 7, 3, 2, 3, 3, 2, 2, 1, 3, 5, 6, 4, 2, 4, 5
OFFSET
1,13
COMMENTS
Is this sequence bounded?
Are there infinitely many null values?
EXAMPLE
The first terms, alongside the values of k such that (n-1-2*k, a(n-1-2*k)), (n-1-k, a(n-1-k)) and (n-1, a(n-1)), are:
n a(n) k's
-- ---- -----
1 0 none
2 0 none
3 0 none
4 1 1
5 0 none
6 1 2
7 0 none
8 1 2
9 1 2
10 0 none
11 0 none
12 1 4
13 2 3,4
14 3 1,4,5
PROG
(C) See Links section.
CROSSREFS
See A308639 for a similar sequence.
Sequence in context: A122587 A276333 A347380 * A356320 A207572 A289623
KEYWORD
nonn,look
AUTHOR
Rémy Sigrist, Jun 13 2019
STATUS
approved