A377601 Number of permutations of the multiset {1^n, 2^n,..., n^n} excluding permutations where all objects of all types are contiguous.

0, 0, 4, 1674, 63062976, 623360743125000, 2670177736637149247308080, 7363615666157189603982585462030330960, 18165723931630806756964027928179555634194028453959680, 53130688706387569792052442448845648519471103327391407016237759999637120

Offset: 0

Author

Mohammad Bakhshandeh, Nov 02 2024

Keywords

• nonn
• easy

Examples

			For n=2, the multiset is {1,1,2,2} and the a(2)=4 permutations counted are 1212, 1221, 2112, 2121 (but neither 1122 nor 2211).
		

Crossrefs

Cf. A000142, A034841.

Formula

a(n) = (n^2)!/(n!)^n - n!.

a(n) = A034841(n) - A000142(n).