A329257 a(n) is the number of numbers k such that a(n-2*k) = a(n-k) and 0 < n-2*k < n-k < n .
0, 0, 1, 0, 0, 2, 1, 1, 2, 0, 1, 1, 2, 1, 2, 3, 4, 1, 2, 2, 4, 1, 1, 3, 5, 1, 1, 3, 3, 3, 3, 8, 3, 5, 2, 4, 2, 4, 2, 4, 3, 4, 4, 5, 1, 4, 1, 2, 4, 4, 5, 3, 1, 5, 5, 3, 4, 5, 7, 3, 5, 3, 6, 8, 5, 2, 4, 8, 3, 0, 6, 8, 1, 3, 3, 10, 4, 4, 9, 4, 4, 7, 9, 5, 3, 4, 6
Offset: 1
Examples
The first terms, alongside the corresponding k's, are:
n a(n) k's
--- ---- ------------
1 0 {}
2 0 {}
3 1 {1}
4 0 {}
5 0 {}
6 2 {1, 2}
7 1 {3}
8 1 {3}
9 2 {1, 4}
10 0 {}
11 1 {4}
12 1 {3}
13 2 {1, 5}
14 1 {3}
15 2 {4, 5}
16 3 {2, 4, 6}
17 4 {2, 3, 4, 5}
Links
- Rémy Sigrist, Table of n, a(n) for n = 1..25000
- Rémy Sigrist, C program for A329257
- Rémy Sigrist, Colored scatterplot of the first 250000 terms (where the color denotes the parity of n)
Programs
-
C
See Links section.