A198801 Number of closed paths of length 19n whose steps are 19th roots of unity.

1, 121645100408832000, 997586474354936812896742294502400000000, 66507379539349211518364492838558005847493108039680000000000000, 11256716378122801825351385824819232115042452248916289339300576523719750000000000000000

Offset

0,2

Comments

Equivalently, the number of paths of length 19n in Z^19 from {0}^19 to {n}^19. - Andrew Howroyd, Nov 01 2018

Links

Andrew Howroyd, Table of n, a(n) for n = 0..40

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) = (19*n)!/(n!)^19. - Andrew Howroyd, Nov 01 2018

Prog

(PARI) a(n) = (19*n)!/(n!)^19; \\ Andrew Howroyd, Nov 01 2018

Crossrefs

Row n=19 of A187783, column k=19 of A089759.

Sequence in context: A095433 A099727 A011530 * A317259 A317914 A317255

Adjacent sequences: A198798 A198799 A198800 * A198802 A198803 A198804

Keyword

nonn

Author

Simon Plouffe, Oct 30 2011

Extensions

Sequence redefined and a(2)-a(4) from Andrew Howroyd, Nov 01 2018

Status

approved