A367128 a(1)=a(2)=1; thereafter a(n) is the radius of the sequence's digraph, where jumps from location i to i+-a(i) are permitted (within 1..n-1).
1, 1, 1, 1, 2, 2, 2, 3, 3, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 10, 10, 10, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10
Offset: 1
Keywords
Examples
To find a(5), we can look at the eccentricity of each location:
i = 1 2 3 4
a(i) = 1, 1, 1, 1
1 <-> 1 <-> 1 <-> 1
eccentricity = 3 2 2 3
i=1 has eccentricity 3 because it requires up to 3 jumps to reach any other location (3 to i=4), and similarly i=4 has eccentricity 3 too.
i=2 and i=3 have eccentricity 2 as they require at most 2 jumps to reach anywhere.
The smallest eccentricity of any location is 2, which makes 2 the radius of the sequence's digraph, so a(5)=2.
Links
- Kevin Ryde, Table of n, a(n) for n = 1..10000
- Kevin Ryde, C Code
- Wikipedia, Distance (graph theory)
Programs
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C
/* See links */
Comments