login
A227052
a(n) = (n^2)! / (n^2-n)! = number of ways of placing n labeled balls into n^2 labeled boxes with at most one ball in each box.
0
1, 1, 12, 504, 43680, 6375600, 1402410240, 432938943360, 178462987637760, 94670977328928000, 62815650955529472000, 50963773003971232204800, 49633807532904958383820800, 57141374006987657125324185600, 76763145767753986733306290176000, 119005648371962652004288345681920000
OFFSET
0,3
MATHEMATICA
Table[(n^2)!/(n^2-n)!, {n, 0, 20}] (* Harvey P. Dale, Aug 10 2017 *)
PROG
(Python)
import math
for n in range(20):
print(math.factorial(n*n)//math.factorial(n*n-n), end=', ')
CROSSREFS
Cf. A014062.
Sequence in context: A220258 A220322 A279302 * A176731 A211085 A197600
KEYWORD
nonn,easy
AUTHOR
Alex Ratushnyak, Jun 29 2013
STATUS
approved