OFFSET
0,3
COMMENTS
From Tilman Piesk, Oct 30 2014: (Start)
Column 7 of A187783.
Number of permutations of a multiset that contains n different elements 7 times.
Or in other words (the former title of this sequence):
Number of 7*n X n 0..1 arrays with row sums 1 and column sums 7.
(End)
LINKS
Tilman Piesk, Table of n, a(n) for n = 0..54 (first 14 terms from R. H. Hardin)
FORMULA
a(n) = (7n)!/(7!^n).
EXAMPLE
a(3) = (7*3)!/(7!^3) = 399072960 is the number of permutations of a multiset that contains 3 different elements 7 times, e.g., {1,1,1,1,1,1,1,2,2,2,2,2,2,2,3,3,3,3,3,3,3}.
MAPLE
MATHEMATICA
Table[(7 n)! / (5040^n), {n, 0, 10}] (* Vincenzo Librandi, Nov 01 2014 *)
PROG
(Magma) [Factorial(7*n)/(5040^n): n in [0..20]]; // Vincenzo Librandi, Nov 01 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Feb 06 2010
EXTENSIONS
Name changed by Tilman Piesk, Oct 30 2014
STATUS
approved