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 A331462 Triangle read by rows: T(n,k) is the number of n X n binary matrices with k=0..n^2 ones forming a polyomino, under action of dihedral group of the square D_4. 2
 0, 0, 1, 0, 1, 1, 1, 1, 0, 3, 2, 5, 6, 10, 8, 7, 3, 1, 0, 3, 4, 8, 17, 33, 68, 119, 195, 261, 300, 257, 169, 66, 20, 3, 1, 0, 6, 6, 16, 32, 82, 189, 470, 1076, 2422, 5010, 9732, 17145, 27399, 38680, 47560, 49325, 41872, 27864, 14095, 5280, 1470, 302, 48, 6, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,10 COMMENTS By forming a polyomino it is meant that there is at least one 1 and that all the 1's are connected horizontally or vertically. LINKS Jean-Luc Manguin, Table of n, a(n) for n = 0..97 Jean-Luc Manguin, Illustration of a(3) and comparison with A268416 EXAMPLE Triangle begins:   0;   0, 1;   0, 1, 1, 1, 1;   0, 3, 2, 5, 6, 10, 8, 7, 3, 1;   0, 3, 4, 8, 17, 33, 68, 119, 195, 261, 300, 257, 169, 66, 20, 3, 1;   ... CROSSREFS Cf. A054252, A268416. Sequence in context: A194105 A194012 A255556 * A308410 A286111 A338209 Adjacent sequences:  A331459 A331460 A331461 * A331463 A331464 A331465 KEYWORD nonn,tabf AUTHOR Jean-Luc Manguin, Jan 17 2020 STATUS approved

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Last modified August 3 08:21 EDT 2021. Contains 346435 sequences. (Running on oeis4.)