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A227639 Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having determinant equal to one, with rows and columns of the latter in nondecreasing lexicographic order 1

%I #4 Jul 18 2013 21:38:30

%S 4,23,127,667,3202,13740,53575,192191,640831,2002960,5909556,16555375,

%T 44257697,113385871,279415526,664438386,1528929898,3412860357,

%U 7406164606,15655003700,32288642035,65081639197,128377414029,248137470904

%N Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having determinant equal to one, with rows and columns of the latter in nondecreasing lexicographic order

%C Column 4 of A227641

%H R. H. Hardin, <a href="/A227639/b227639.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (1/2534272925184000)*n^19 - (1/36377123328000)*n^18 + (67/29640619008000)*n^17 - (23/219469824000)*n^16 + (19/4245696000)*n^15 - (1120937/7846046208000)*n^14 + (30866519/7846046208000)*n^13 - (315413129/3621252096000)*n^12 + (325169513/201180672000)*n^11 - (668686973/27433728000)*n^10 + (17219161039/57480192000)*n^9 - (639427718879/219469824000)*n^8 + (85152990271801/3923023104000)*n^7 - (121633558587211/1069915392000)*n^6 + (4714045506851/14859936000)*n^5 + (29982367841021/50295168000)*n^4 - (119301334227941/11027016000)*n^3 + (805259895738317/15437822400)*n^2 - (4914764430377/38798760)*n + 130960 for n>9

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jul 18 2013

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Last modified March 28 12:26 EDT 2024. Contains 371254 sequences. (Running on oeis4.)