login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A339490 Number of longest simple paths in the divisor graph of {1,...,n}. 2
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 (list; graph; refs; listen; history; text; internal format)
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: A136534 A121175 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 17 00:17 EDT 2021. Contains 345080 sequences. (Running on oeis4.)