A333734 - OEIS

%I #8 Oct 15 2024 00:02:12

%S 1,1,2,5,43,1856,1217727,8597641912,646296747486387,

%T 535435113671568180963,5081029530811947425598907884,

%U 570680215340337514993573217774604779,779646755088025699677478853259568262608053838

%N Number of non-isomorphic n X n nonnegative integer matrices with all row and column sums equal to n up to permutations of rows and columns.

%e The a(2) = 2 matrices are:

%e   [1 1]  [2 0]

%e   [1 1]  [0 2]

%e .

%e The a(3) = 5 matrices are:

%e   [1 1 1]   [2 1 0]   [2 1 0]   [3 0 0]   [3 0 0]

%e   [1 1 1]   [1 1 1]   [0 2 1]   [0 2 1]   [0 3 0]

%e   [1 1 1]   [0 1 2]   [1 0 2]   [0 1 2]   [0 0 3]

%Y Main diagonal of A333733 and A377060.

%Y Cf. A110058.

%K nonn,more

%O 0,3

%A _Andrew Howroyd_, Apr 04 2020

%E a(11)-a(12) from _Andrew Howroyd_, Oct 14 2024