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

1, 121645100408832000, 997586474354936812896742294502400000000, 66507379539349211518364492838558005847493108039680000000000000, 11256716378122801825351385824819232115042452248916289339300576523719750000000000000000

Offset: 0

Author

Simon Plouffe, Oct 30 2011

Keywords

• nonn

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.

Crossrefs

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

Programs

PARI

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

Formula

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

Extensions

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