login
A198809
Number of closed paths of length 11n whose steps are 11th roots of unity.
1
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
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
KEYWORD
nonn
AUTHOR
Simon Plouffe, Oct 30 2011
EXTENSIONS
Sequence redefined and a(2)-a(6) from Andrew Howroyd, Nov 01 2018
STATUS
approved