A301771 Number of odd chordless cycles in the n-Andrásfai graph.

0, 1, 8, 33, 100, 255, 584, 1242, 2496, 4785, 8800, 15587, 26676, 44239, 71280, 111860, 171360, 256785, 377112, 543685, 770660, 1075503, 1479544, 2008590, 2693600, 3571425, 4685616, 6087303, 7836148, 10001375, 12662880, 15912424, 19854912, 24609761, 30312360

Offset

1,3

Comments

a(11) - a(35) were computed from the definition, not from the conjectured formula. - Pontus von Brömssen, Oct 09 2022

Links

Eric W. Weisstein, Table of n, a(n) for n = 1..42

Eric Weisstein's World of Mathematics, Andrásfai Graph.

Eric Weisstein's World of Mathematics, Chordless Cycle.

Wikipedia, Andrásfai graph.

R. J. Mathar, Illustrations

Formula

Conjectured g.f.: x*(x - 3*x^3 + 4*x^4 + x^5)/(1 - x)^8.

Crossrefs

Cf. A234602.

Sequence in context: A070736 A051836 A278670 * A070051 A087235 A222346

Adjacent sequences: A301768 A301769 A301770 * A301772 A301773 A301774

Keyword

nonn

Author

Eric W. Weisstein, Mar 26 2018

Extensions

a(8)-a(10) from Andrew Howroyd, Mar 26 2018

a(11)-a(35) from Pontus von Brömssen, Oct 09 2022

Removed program that was based on the conjectured generating function. - N. J. A. Sloane, Feb 09 2024

Status

approved