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Square of A(n,m) read by antidiagonals. A(n,m) = number of set partitions of [7n] into 7-element subsets {i, i+k, i+2k, i+3k, i+4k, i+5k, i+6k} with 1 <= k <= m.
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%I #10 Feb 13 2023 16:17:18

%S 1,1,1,1,2,1,1,2,3,1,1,2,4,5,1,1,2,4,7,8,1,1,2,4,10,13,13,1,1,2,4,10,

%T 19,24,21,1,1,2,4,10,20,41,44,34,1,1,2,4,10,20,43,84,81,55,1,1,2,4,10,

%U 20,56,89,180,149,89,1,1,2,4,10,20,56,115,192,372,274,144,1

%N Square of A(n,m) read by antidiagonals. A(n,m) = number of set partitions of [7n] into 7-element subsets {i, i+k, i+2k, i+3k, i+4k, i+5k, i+6k} with 1 <= k <= m.

%F A(n,m) = A104433(n) = A104443(n,7) for m >= floor((7*n - 1) / 6).

%e Square array begins:

%e 1, 1, 1, 1, 1, 1, 1, 1, 1, ...

%e 1, 2, 2, 2, 2, 2, 2, 2, 2, ...

%e 1, 3, 4, 4, 4, 4, 4, 4, 4, ...

%e 1, 5, 7, 10, 10, 10, 10, 10, 10, ...

%e 1, 8, 13, 19, 20, 20, 20, 20, 20, ...

%e 1, 13, 24, 41, 43, 56, 56, 56, 56, ...

%e 1, 21, 44, 84, 89, 115, 116, 117, 117, ...

%e 1, 34, 81, 180, 192, 267, 269, 322, 323, ...

%e 1, 55, 149, 372, 404, 592, 597, 704, 744, ...

%e 1, 89, 274, 785, 860, 1372, 1384, 1741, 1822, ...

%e 1, 144, 504, 1637, 1816, 3028, 3060, 3886, 4088, ...

%e 1, 233, 927, 3442, 3857, 7038, 7114, 9742, 10374, ...

%e ...

%Y Columns 1..3 are A000012, A000045(n+1), A000073(n+2).

%Y Cf. A104433, A104443, A360333..A360335, A360491, A360492.

%K nonn,tabl

%O 1,5

%A _Peter Dolland_, Feb 09 2023