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A227261 Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having a sum of two or less, with rows and columns of the latter in lexicographically nondecreasing order 1

%I

%S 5,50,353,2201,11932,57146,244818,951917,3403038,11297855,35123154,

%T 102968348,286360987,759331583,1928166887,4706232142,11076831313,

%U 25210805133,55622829033,119222502647,248739253915,506020952898

%N Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having a sum of two or less, with rows and columns of the latter in lexicographically nondecreasing order

%C Column 4 of A227263

%H R. H. Hardin, <a href="/A227261/b227261.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (1/1689515283456000)*n^19 + (43/1067062284288000)*n^18 + (1/1097800704000)*n^17 + (1/24908083200)*n^16 + (2161/2615348736000)*n^15 + (7723/10461394944000)*n^14 + (76931/201180672000)*n^13 + (38351/48283361280)*n^12 - (9767641/402361344000)*n^11 + (9434683/6967296000)*n^10 - (3668820107/402361344000)*n^9 - (5124736597/80472268800)*n^8 + (150774753091/72648576000)*n^7 - (42587741190289/3923023104000)*n^6 - (18276563116219/163459296000)*n^5 + (6577553955799/3113510400)*n^4 - (743180805841567/51459408000)*n^3 + (63341814516853/1286485200)*n^2 - (326223749821/4476780)*n + 17722 for n>9

%e Some solutions for n=4

%e ..1..0..0..0....1..1..1..0....1..1..0..0....1..1..1..0....1..1..1..1

%e ..1..1..1..0....1..1..0..0....1..0..0..0....1..1..1..0....1..1..1..0

%e ..1..1..1..1....1..0..0..0....1..0..1..1....1..1..1..0....0..0..0..0

%e ..1..1..1..1....1..1..0..0....1..0..1..1....1..0..1..1....0..0..0..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Jul 04 2013

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Last modified February 8 04:10 EST 2023. Contains 360134 sequences. (Running on oeis4.)