A198807 Number of closed paths of length 13n whose steps are 13th roots of unity.

1, 6227020800, 49229914688306352000000, 1561776277448122046153927884800000000, 92024242230271040357108320801872044844750000000000, 7708574168669332219803079339976372645861971547841327593737420800

Offset

0,2

Comments

Equivalently, the number of paths of length 13n in Z^13 from {0}^13 to {n}^13. - Andrew Howroyd, Nov 01 2018

Links

Table of n, a(n) for n=0..5.

Gilbert Labelle and Annie Lacasse, Closed paths whose steps are roots of unity, in FPSAC 2011, Reykjavik, Iceland DMTCS proc. AO, 2011, 599-610.

Formula

a(n) = (13*n)!/(n!)^13. - Andrew Howroyd, Nov 01 2018

Prog

(PARI) a(n) = (13*n)!/(n!)^13; \\ Andrew Howroyd, Nov 01 2018

Crossrefs

Row n=13 of A187783, column k=13 of A089759.

Sequence in context: A004675 A011524 A172534 * A358489 A281222 A258365

Adjacent sequences: A198804 A198805 A198806 * A198808 A198809 A198810

Keyword

nonn

Author

Simon Plouffe, Oct 30 2011

Extensions

Sequence redefined and a(2)-a(5) from Andrew Howroyd, Nov 01 2018

Status

approved