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 A252857 Number of (n+2) X (4+2) 0..2 arrays with every consecutive three elements in every row, column, diagonal and antidiagonal having exactly two distinct values, and new values 0 upwards introduced in row major order. 1
 1719, 1296, 1962, 3582, 7002, 13590, 26766, 52650, 104796, 207414, 410922, 815634, 1620126, 3212352, 6373728, 12654630, 25115112, 49827690, 98894880, 196294230, 389531628, 773007606, 1534206006, 3044825712, 6042454650, 11991793788 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = a(n-2) + 4*a(n-3) + 6*a(n-4) - a(n-5) - 5*a(n-6) - 5*a(n-7) + 2*a(n-9) - a(n-10) for n>12. Empirical g.f.: 9*x*(191 + 144*x + 27*x^2 - 510*x^3 - 1162*x^4 - 433*x^5 + 395*x^6 + 733*x^7 + 170*x^8 - 284*x^9 + 63*x^10 + 26*x^11) / ((1 - x)*(1 + x)*(1 + x + x^2)*(1 - x - 3*x^3 - 3*x^4 + 3*x^5 - x^6)). - Colin Barker, Dec 07 2018 EXAMPLE Some solutions for n=4: ..0..1..0..0..2..2....0..0..1..1..2..2....0..0..1..1..2..1....0..1..0..0..2..0 ..0..0..1..1..2..1....2..1..1..0..1..0....0..2..0..2..2..1....2..2..0..0..1..1 ..2..1..1..0..0..2....2..0..0..1..1..2....2..0..0..1..1..2....2..1..2..1..2..1 ..2..0..0..1..0..1....1..1..0..1..0..0....2..0..2..2..1..2....1..2..2..1..1..0 ..1..1..0..0..2..2....1..1..2..2..0..0....1..1..2..2..0..0....1..2..1..2..2..0 ..1..1..2..1..2..2....0..2..2..1..2..1....1..0..1..0..1..0....0..0..2..2..1..2 CROSSREFS Column 4 of A252861. Sequence in context: A252610 A237932 A276458 * A234906 A205195 A200958 Adjacent sequences: A252854 A252855 A252856 * A252858 A252859 A252860 KEYWORD nonn AUTHOR R. H. Hardin, Dec 23 2014 STATUS approved

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Last modified March 29 05:10 EDT 2023. Contains 361596 sequences. (Running on oeis4.)