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 A250426 Number of (n+1)X(2+1) 0..1 arrays with nondecreasing sum of every two consecutive values in every row and column. 1
 36, 108, 324, 720, 1600, 3000, 5625, 9450, 15876, 24696, 38416, 56448, 82944, 116640, 164025, 222750, 302500, 399300, 527076, 679536, 876096, 1107288, 1399489, 1739010, 2160900, 2646000, 3240000, 3916800, 4734976, 5659776, 6765201, 8005878 (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) = 2*a(n-1) + 4*a(n-2) - 10*a(n-3) - 5*a(n-4) + 20*a(n-5) - 20*a(n-7) + 5*a(n-8) + 10*a(n-9) - 4*a(n-10) - 2*a(n-11) + a(n-12). Empirical for n mod 2 = 0: a(n) = (1/256)*n^6 + (11/128)*n^5 + (49/64)*n^4 + (113/32)*n^3 + (71/8)*n^2 + (23/2)*n + 6. Empirical for n mod 2 = 1: a(n) = (1/256)*n^6 + (11/128)*n^5 + (199/256)*n^4 + (237/64)*n^3 + (2511/256)*n^2 + (1755/128)*n + (2025/256). a(n+1)=A202093(n). - R. J. Mathar, Dec 04 2014 Empirical g.f.: x*(36 + 36*x - 36*x^2 + 124*x^4 - 20*x^5 - 115*x^6 + 40*x^7 + 56*x^8 - 26*x^9 - 11*x^10 + 6*x^11) / ((1 - x)^7*(1 + x)^5). - Colin Barker, Nov 14 2018 EXAMPLE Some solutions for n=6: ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..0....0..0..1 ..0..1..0....0..0..0....0..0..1....0..0..1....0..0..0....0..1..0....0..0..1 ..0..1..1....0..0..0....0..0..1....0..0..0....0..0..1....0..1..0....0..1..1 ..0..1..1....0..0..0....0..0..1....0..1..1....0..0..1....0..1..0....0..0..1 ..0..1..1....0..0..0....0..0..1....0..0..1....0..1..1....0..1..0....0..1..1 ..1..1..1....0..1..1....0..1..1....1..1..1....1..1..1....0..1..1....0..0..1 ..0..1..1....0..1..1....0..1..1....1..0..1....1..1..1....1..1..1....1..1..1 CROSSREFS Column 2 of A250432. Sequence in context: A076768 A282853 A162940 * A176685 A199260 A033575 Adjacent sequences:  A250423 A250424 A250425 * A250427 A250428 A250429 KEYWORD nonn AUTHOR R. H. Hardin, Nov 22 2014 STATUS approved

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Last modified December 12 07:02 EST 2018. Contains 318051 sequences. (Running on oeis4.)