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 A208704 Number of nX3 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors. 2
 4, 28, 196, 1372, 9604, 67228, 470596, 3294172, 23059204, 161414428, 1129900996, 7909306972, 55365148804, 387556041628, 2712892291396, 18990246039772, 132931722278404, 930522055948828, 6513654391641796, 45595580741492572 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 3 of A208709. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 7*a(n-1). Empirical: a(n) = (A198480(n)+1)*2 = (A024075(n)+1)*4. [Martin Ettl, Nov 09 2012; revised Nov 13 2012] EXAMPLE Some solutions for n=4 ..0..0..0....0..1..1....0..0..1....0..1..1....0..1..1....0..1..1....0..0..1 ..1..0..1....1..0..1....0..0..1....0..1..1....1..0..0....1..0..1....0..1..1 ..1..0..1....0..1..0....0..0..1....0..1..1....1..1..1....1..1..1....0..0..0 ..1..0..1....0..1..0....1..1..1....0..1..1....1..0..1....1..0..1....0..1..0 CROSSREFS Cf. A270471. Sequence in context: A155611 A218175 A002903 * A270471 A019482 A198630 Adjacent sequences:  A208701 A208702 A208703 * A208705 A208706 A208707 KEYWORD nonn AUTHOR R. H. Hardin, Mar 01 2012 STATUS approved

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Last modified August 13 22:26 EDT 2020. Contains 336464 sequences. (Running on oeis4.)