cp's OEIS Frontend

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.

A207502 Number of 5Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically.

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%I A207502 #7 Jul 22 2025 20:30:53
%S A207502 14,196,932,3939,14253,41938,122061,319798,813724,2009628,4807523,
%T A207502 11399943,26611726,61691519,142452960,327544544,752851062,1729196533,
%U A207502 3973096971,9138133990,21035634301,48483600980,111872215076,258410783006
%N A207502 Number of 5Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically.
%C A207502 Row 5 of A207500
%H A207502 R. H. Hardin, <a href="/A207502/b207502.txt">Table of n, a(n) for n = 1..210</a>
%F A207502 Empirical: a(n) = 5*a(n-1) -a(n-2) -24*a(n-3) +99*a(n-5) -2*a(n-6) -235*a(n-7) -24*a(n-8) +372*a(n-9) +59*a(n-10) -396*a(n-11) +66*a(n-12) +186*a(n-13) -280*a(n-14) -50*a(n-15) +588*a(n-16) -124*a(n-17) -524*a(n-18) +148*a(n-19) +326*a(n-20) -212*a(n-21) -80*a(n-22) +226*a(n-23) -98*a(n-24) -116*a(n-25) +70*a(n-26) +86*a(n-27) -87*a(n-28) +21*a(n-29) +13*a(n-30) -4*a(n-31) -20*a(n-32) +17*a(n-33) -4*a(n-34) -a(n-35) +2*a(n-37) -a(n-38)
%e A207502 Some solutions for n=4
%e A207502 ..1..0..0..1....0..1..0..0....1..1..1..0....1..1..0..0....0..0..1..0
%e A207502 ..0..1..0..0....1..0..1..0....1..0..1..0....1..1..1..1....1..1..0..1
%e A207502 ..1..1..0..1....1..1..0..0....0..1..0..0....0..0..1..0....1..0..1..0
%e A207502 ..1..0..0..1....1..0..1..0....1..0..1..0....1..1..0..1....0..1..0..1
%e A207502 ..0..1..0..0....1..1..0..0....1..1..0..0....1..1..1..0....1..1..1..1
%K A207502 nonn
%O A207502 1,1
%A A207502 _R. H. Hardin_ Feb 18 2012