A172603 a(n) = (7n)!/(7!^n).

1, 1, 3432, 399072960, 472518347558400, 3177459078523411968000, 85722533226982363751829504000, 7363615666157189603982585462030336000, 1707750599894443404262670865631874246246400000

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

A172603:=n->(7*n)!/(5040^n): seq(A172603(n), n=0..10); # Wesley Ivan Hurt, Nov 01 2014

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

Sequence in context: A362172 A177308 A177309 * A172559 A172658 A172757

Adjacent sequences: A172600 A172601 A172602 * A172604 A172605 A172606

Keyword

nonn,easy

Author

R. H. Hardin, Feb 06 2010

Extensions

Name changed by Tilman Piesk, Oct 30 2014

Status

approved