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 A247417 Number of nonisomorphic binary n X n matrices with two 1's per column under row and column permutations. 5
 1, 3, 11, 35, 132, 471, 1806, 7042, 28494, 118662, 510517, 2262738, 10337474, 48625631, 235357470, 1171163995, 5986424739, 31403695142, 168913667164, 930739116386, 5249162406890, 30275048671498, 178428441191289, 1073737691984694, 6592909590432719 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 LINKS Andrew Howroyd, Table of n, a(n) for n = 2..50 StackExchange, How many arrays with crossed cells, order of rows/columns irrelevant, Dec 13 2013 MAPLE Using the uploaded program the call is seq(matrix_marks(n, 2), n=3..15); PROG (PARI) \\ See A304942 for Blocks a(n) = Blocks(n, n, 2); \\ Andrew Howroyd, May 24 2018 CROSSREFS Column k=2 of A304942. Cf. A247596, A247597, A247598. Sequence in context: A320087 A014335 A147474 * A222286 A119143 A119092 Adjacent sequences:  A247414 A247415 A247416 * A247418 A247419 A247420 KEYWORD nonn AUTHOR Marko Riedel, Sep 21 2014 EXTENSIONS Terms a(17) and beyond from Andrew Howroyd, May 23 2018 STATUS approved

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Last modified August 7 17:44 EDT 2020. Contains 336278 sequences. (Running on oeis4.)