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A246107 Number of inequivalent n X n matrices with entries from [n], where equivalence means permutations of rows or columns. 2
1, 1, 7, 738, 7880456, 20834113243925, 19909522361922032493690, 10114980502439545115146468340980932, 3861175753082201291221743022346066208381644388448, 1493197587365241166689220567691206411606485768307602552950789523519 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..26

FORMULA

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

MAPLE

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

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

       b(n-i*j, i-1))[], j=1..n/i)]))

    end:

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

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

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

    end:

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

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

CROSSREFS

Main diagonal of A246106.

Sequence in context: A249834 A064571 A111476 * A156618 A027685 A248385

Adjacent sequences:  A246104 A246105 A246106 * A246108 A246109 A246110

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Aug 13 2014

STATUS

approved

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Last modified February 27 22:21 EST 2020. Contains 332312 sequences. (Running on oeis4.)