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

Author

Peter Luschny, Dec 27 2020

Keywords

• nonn
• more
• hard

Examples

			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.

Extensions

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