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A331510 Array read by antidiagonals: A(n,k) is the number of nonequivalent binary matrices with k columns and any number of distinct nonzero rows with n ones in every column up to permutation of rows and columns. 7

%I #15 Feb 09 2020 02:43:15

%S 1,1,1,1,1,1,1,2,0,1,1,3,1,0,1,1,5,4,0,0,1,1,7,12,3,0,0,1,1,11,36,23,

%T 1,0,0,1,1,15,124,191,30,0,0,0,1,1,22,412,2203,837,23,0,0,0,1,1,30,

%U 1500,31313,41664,2688,12,0,0,0,1

%N Array read by antidiagonals: A(n,k) is the number of nonequivalent binary matrices with k columns and any number of distinct nonzero rows with n ones in every column up to permutation of rows and columns.

%F A(n,k) = 0 for k > 0, n > 2^(k-1).

%F A(n,k) = A(2^(k-1) - n, k) for k > 0, n <= 2^(k-1).

%e Array begins:

%e =================================

%e n\k | 0 1 2 3 4 5 6 7

%e ----+----------------------------

%e 0 | 1 1 1 1 1 1 1 1 ...

%e 1 | 1 1 2 3 5 7 11 15 ...

%e 2 | 1 0 1 4 12 36 124 412 ...

%e 3 | 1 0 0 3 23 191 2203 ...

%e 4 | 1 0 0 1 30 837 ...

%e 5 | 1 0 0 0 23 ...

%e ...

%e The A(2,3) = 4 matrices are:

%e [1 1 1] [1 1 0] [1 1 1] [1 1 0]

%e [1 0 0] [1 0 1] [1 1 0] [1 0 1]

%e [0 1 0] [0 1 0] [0 0 1] [0 1 1]

%e [0 0 1] [0 0 1]

%Y Rows n=1..3 are A000041, A331717, A331718.

%Y Column k=5 is A331719.

%Y Cf. A188445, A330942, A331461, A331508, A331509.

%K nonn,tabl,more

%O 0,8

%A _Andrew Howroyd_, Jan 18 2020

%E a(58)-a(65) from _Andrew Howroyd_, Feb 08 2020

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Last modified April 19 03:57 EDT 2024. Contains 371782 sequences. (Running on oeis4.)