A198809 Number of closed paths of length 11n whose steps are 11th roots of unity.

1, 39916800, 548828480360160000, 23934366266775567482880000000, 1746930746117010628955362040959500000000, 170878335353097656943918169452451079403744627916800, 20193738534370392855946567010492898163504440783192016158720000

Offset

0,2

Comments

Equivalently, the number of paths of length 11n in Z^11 from {0}^11 to {n}^11. - Andrew Howroyd, Nov 01 2018

Links

Andrew Howroyd, Table of n, a(n) for n = 0..50

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) = (11*n)!/(n!)^11. - Andrew Howroyd, Nov 01 2018

Prog

(PARI) a(n) = (11*n)!/(n!)^11; \\ Andrew Howroyd, Nov 01 2018

Crossrefs

Row n=11 of A187783, column k=11 of A089759.

Sequence in context: A072237 A011522 A172539 * A181727 A307477 A218390

Adjacent sequences: A198806 A198807 A198808 * A198810 A198811 A198812

Keyword

nonn

Author

Simon Plouffe, Oct 30 2011

Extensions

Sequence redefined and a(2)-a(6) from Andrew Howroyd, Nov 01 2018

Status

approved