This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A317764 #4 Aug 06 2018 11:52:19 %S A317764 1,2,2,4,6,4,8,10,10,8,16,20,16,20,16,32,42,28,28,42,32,64,89,52,43, %T A317764 52,89,64,128,190,100,72,72,100,190,128,256,407,196,127,109,127,196, %U A317764 407,256,512,873,388,232,177,177,232,388,873,512,1024,1874,772,432,302,266,302 %N A317764 T(n,k)=Number of nXk 0..1 arrays with every element unequal to 0, 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. %C A317764 Table starts %C A317764 ...1...2...4...8..16...32...64..128..256..512.1024..2048..4096..8192.16384 %C A317764 ...2...6..10..20..42...89..190..407..873.1874.4024..8642.18561.39866.85627 %C A317764 ...4..10..16..28..52..100..196..388..772.1540.3076..6148.12292.24580.49156 %C A317764 ...8..20..28..43..72..127..232..432..813.1539.2922..5557.10577.20141.38362 %C A317764 ..16..42..52..72.109..177..302..532..955.1733.3164..5796.10637.19541.35918 %C A317764 ..32..89.100.127.177..266..425..709.1217.2126.3753..6666.11882.21223.37952 %C A317764 ..64.190.196.232.302..425..639.1012.1663.2801.4792..8278.14385.25088.43852 %C A317764 .128.407.388.432.532..709.1012.1529.2413.3927.6524.10984.18651.31842.54552 %C A317764 .256.873.772.813.955.1217.1663.2413.3674.5798.9381.15434.25672.43007.72386 %H A317764 R. H. Hardin, <a href="/A317764/b317764.txt">Table of n, a(n) for n = 1..1300</a> %F A317764 Empirical for column k: %F A317764 k=1: a(n) = 2*a(n-1) %F A317764 k=2: a(n) = 2*a(n-1) +a(n-2) -a(n-3) -a(n-4) for n>6 %F A317764 k=3: a(n) = 3*a(n-1) -2*a(n-2) for n>3 %F A317764 k=4: a(n) = 2*a(n-1) +a(n-2) -2*a(n-3) -a(n-4) +a(n-5) for n>6 %F A317764 k=5: a(n) = 2*a(n-1) -a(n-4) for n>6 %F A317764 k=6: a(n) = 2*a(n-1) +a(n-2) -2*a(n-3) -a(n-4) +a(n-7) for n>10 %F A317764 k=7: a(n) = 3*a(n-1) -2*a(n-2) -a(n-4) +a(n-5) -a(n-6) +a(n-7) for n>11 %e A317764 Some solutions for n=5 k=4 %e A317764 ..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..1. .0..1..1..0 %e A317764 ..1..1..1..1. .0..0..0..0. .0..0..0..0. .0..0..1..1. .1..1..0..0 %e A317764 ..1..1..1..1. .0..0..0..0. .0..0..0..0. .0..1..1..1. .1..0..0..0 %e A317764 ..1..1..1..1. .0..0..0..0. .0..0..0..0. .1..1..1..1. .0..0..0..0 %e A317764 ..0..0..0..0. .1..1..1..1. .0..0..0..1. .0..0..0..0. .0..0..0..0 %Y A317764 Column 1 is A000079(n-1). %Y A317764 Column 3 is A003461 for n>1. %K A317764 nonn,tabl %O A317764 1,2 %A A317764 _R. H. Hardin_, Aug 06 2018