cp's OEIS Frontend

A203833 Number of (n+1)X7 0..2 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements.

%I A203833 #7 Jul 22 2025 17:32:51
%S A203833 140625,11669859,1043088057,95763046491,8882824128417,827309554361235,
%T A203833 77176081545485769,7204002753036584331,672627208587089667633,
%U A203833 62808488037897381676611,5865153683164077390051033
%N A203833 Number of (n+1)X7 0..2 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements.
%C A203833 Column 6 of A203835
%H A203833 R. H. Hardin, <a href="/A203833/b203833.txt">Table of n, a(n) for n = 1..210</a>
%F A203833 Empirical: a(n) = 117*a(n-1) -614*a(n-2) -193608*a(n-3) +4171896*a(n-4) +11415328*a(n-5) -842180224*a(n-6) +3384845504*a(n-7) +50528534400*a(n-8) -356768428544*a(n-9) -786566761984*a(n-10) +10681051645952*a(n-11) -6785526038528*a(n-12) -118510105321472*a(n-13) +197530250887168*a(n-14) +559297782349824*a(n-15) -1309510355714048*a(n-16) -1087672042455040*a(n-17) +3564507406925824*a(n-18) +719985279238144*a(n-19) -4461650060509184*a(n-20) +91947477762048*a(n-21) +2549613680656384*a(n-22) -206006306996224*a(n-23) -619282299879424*a(n-24) +65421579386880*a(n-25) +47138239152128*a(n-26) -8245531901952*a(n-27) +260919263232*a(n-28)
%e A203833 Some solutions for n=4
%e A203833 ..0..2..0..1..2..2..1....1..2..2..1..2..2..1....2..2..1..1..1..1..0
%e A203833 ..1..0..2..0..1..2..2....0..1..2..2..1..2..2....0..2..2..1..1..1..1
%e A203833 ..2..1..0..2..0..1..2....1..2..2..2..2..2..1....2..1..2..2..1..1..0
%e A203833 ..2..2..1..0..2..0..1....1..1..2..0..2..1..2....1..0..1..2..2..1..1
%e A203833 ..1..2..2..1..0..2..0....2..1..1..2..2..2..2....2..1..1..1..2..2..1
%K A203833 nonn
%O A203833 1,1
%A A203833 _R. H. Hardin_ Jan 06 2012