A339490 Number of longest simple paths in the divisor graph of {1,...,n}.

1, 2, 2, 4, 8, 4, 8, 16, 16, 40, 40, 8, 12, 24, 88, 176, 192, 48, 64, 224, 704, 896, 896, 32, 140, 72, 72, 312, 312, 88, 88, 176

Offset

1,2

Links

Table of n, a(n) for n=1..32.

Example

The longest paths for n = 13. The ones marked with (*) are also the longest paths for n = 12.
[5, 10, 2,  8, 4, 12, 6,  3, 9,  1,  7], (*)
[5, 10, 2,  8, 4, 12, 6,  3, 9,  1, 11], (*)
[5, 10, 2,  8, 4, 12, 6,  3, 9,  1, 13],
[7,  1, 5, 10, 2,  8, 4, 12, 6,  3,  9], (*)
[7,  1, 9,  3, 6, 12, 4,  8, 2, 10,  5], (*)
[9,  3, 6, 12, 4,  8, 2, 10, 5,  1,  7], (*)
[9,  3, 6, 12, 4,  8, 2, 10, 5,  1, 11], (*)
[9,  3, 6, 12, 4,  8, 2, 10, 5,  1, 13],
[11, 1, 5, 10, 2,  8, 4, 12, 6,  3,  9], (*)
[11, 1, 9,  3, 6, 12, 4,  8, 2, 10,  5], (*)
[13, 1, 5, 10, 2,  8, 4, 12, 6,  3,  9],
[13, 1, 9,  3, 6, 12, 4,  8, 2, 10,  5].

Crossrefs

Cf. A337125, A339491.

Sequence in context: A366714 A359488 A183397 * A281469 A302623 A302415

Adjacent sequences: A339487 A339488 A339489 * A339491 A339492 A339493

Keyword

nonn,more,hard

Author

Peter Luschny, Dec 27 2020

Extensions

a(14)-a(32) from Pontus von Brömssen, Dec 29 2020

Status

approved