A301648 Number of longest cycles in the n X n grid graph.

0, 1, 5, 6, 226, 1072, 255088, 4638576, 6663430912, 467260456608, 3916162476483538, 1076226888605605706, 51249820944023435573470, 56126499620491437281263608, 14870957102232406137455708164254, 65882516522625836326159786165530572, 95494789899510664733921727510895952184006

Offset

1,3

Comments

a(10) = 467260456608.

Links

Table of n, a(n) for n=1..17.

Eric Weisstein's World of Mathematics, Graph Cycle

Eric Weisstein's World of Mathematics, Grid Graph

Formula

a(2n) = A003763(n).

a(2n+1) = A181584(n). - Andrew Howroyd, Mar 01 2020

Crossrefs

Cf. A137932 (circumference of the (n-1) X (n-1) grid graph).

Cf. A003763 (number of Hamiltonian cycles in the 2n X 2n grid graph).

Cf. A181584 (number of longest cycles in the (2n+1) X (2n+1) grid graph).

Sequence in context: A041411 A103089 A041601 * A041827 A042089 A156191

Adjacent sequences: A301645 A301646 A301647 * A301649 A301650 A301651

Keyword

nonn

Author

Eric W. Weisstein, Mar 25 2018

Extensions

Terms a(9) and beyond from Andrew Howroyd, Mar 01 2020

Status

approved