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 A211911 Number of lower triangular nXn arrays colored with integers 0 upwards introduced in row major order, with no element equal to any horizontal, vertical, diagonal or antidiagonal neighbor, and containing the value n(n+1)/2-2 1
 0, 1, 6, 25, 70, 156, 301, 526, 855, 1315, 1936, 2751, 3796, 5110, 6735, 8716, 11101, 13941, 17290, 21205, 25746, 30976, 36961, 43770, 51475, 60151, 69876, 80731, 92800, 106170, 120931, 137176, 155001, 174505, 195790, 218961, 244126, 271396, 300885 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Column 1 of A211916 LINKS R. H. Hardin, Table of n, a(n) for n = 1..74 FORMULA Empirical: a(n) = (1/8)*n^4 + (1/4)*n^3 - (17/8)*n^2 + (11/4)*n for n>1 EXAMPLE Some solutions for n=4 ..0........0........0........0........0........0........0........0 ..1.2......1.2......1.2......1.2......1.2......1.2......1.2......1.2 ..3.4.5....3.4.5....3.4.5....3.4.5....3.4.5....3.4.5....3.4.1....3.4.5 ..0.6.7.8..6.7.8.1..1.6.7.8..6.7.3.8..6.7.8.7..6.1.7.8..5.6.7.8..6.7.8.3 CROSSREFS Sequence in context: A001664 A096958 A166814 * A133714 A164271 A220275 Adjacent sequences:  A211908 A211909 A211910 * A211912 A211913 A211914 KEYWORD nonn AUTHOR R. H. Hardin Apr 25 2012 STATUS approved

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