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A246107 Number of inequivalent n X n matrices with entries from [n], where equivalence means permutations of rows or columns. 3

%I #13 May 02 2022 10:24:02

%S 1,1,7,738,7880456,20834113243925,19909522361922032493690,

%T 10114980502439545115146468340980932,

%U 3861175753082201291221743022346066208381644388448,1493197587365241166689220567691206411606485768307602552950789523519

%N Number of inequivalent n X n matrices with entries from [n], where equivalence means permutations of rows or columns.

%H Alois P. Heinz, <a href="/A246107/b246107.txt">Table of n, a(n) for n = 0..26</a>

%H <a href="/index/Mat#inequiv">Index to number of inequivalent matrices modulo permutation of rows and columns</a>

%F a(n) = A246106(2n,n).

%p b:= proc(n, i) option remember; `if`(n=0, [[]],

%p `if`(i<1, [], [b(n, i-1)[], seq(map(p->[p[], [i, j]],

%p b(n-i*j, i-1))[], j=1..n/i)]))

%p end:

%p A:= proc(n, k) option remember; add(add(k^add(add(i[2]*j[2]*

%p igcd(i[1], j[1]), j=t), i=s) /mul(i[1]^i[2]*i[2]!, i=s)

%p /mul(i[1]^i[2]*i[2]!, i=t), t=b(n$2)), s=b(n$2))

%p end:

%p a:= n-> A(n$2):

%p seq(a(n), n=0..12);

%Y Main diagonal of A246106.

%K nonn

%O 0,3

%A _Alois P. Heinz_, Aug 13 2014

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Last modified May 9 10:59 EDT 2024. Contains 372350 sequences. (Running on oeis4.)