cp's OEIS Frontend

A208268 Number of nX7 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or left-upward diagonal neighbors.

%I A208268 #7 Jul 22 2025 21:15:59
%S A208268 64,4021,273205,18403423,1240971177,83670667271,5641457245533,
%T A208268 380372051615157,25646375739266275,1729192685453990877,
%U A208268 116589859961103508219,7861006788319434001589,530024032549172830292655
%N A208268 Number of nX7 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or left-upward diagonal neighbors.
%C A208268 Column 7 of A208269
%H A208268 R. H. Hardin, <a href="/A208268/b208268.txt">Table of n, a(n) for n = 1..210</a>
%F A208268 Empirical: a(n) = 77*a(n-1) -429*a(n-2) -16791*a(n-3) +132938*a(n-4) +1140609*a(n-5) -11250708*a(n-6) -21101443*a(n-7) +356560316*a(n-8) -276630106*a(n-9) -3595865197*a(n-10) +5253257444*a(n-11) +16399879057*a(n-12) -30419637636*a(n-13) -37486637674*a(n-14) +87632998667*a(n-15) +40083109062*a(n-16) -140235056122*a(n-17) -7589163210*a(n-18) +128111780723*a(n-19) -23221600421*a(n-20) -65939015129*a(n-21) +21868944788*a(n-22) +18307048178*a(n-23) -8259596531*a(n-24) -2431120428*a(n-25) +1497147381*a(n-26) +85285300*a(n-27) -123174410*a(n-28) +8581030*a(n-29) +3300116*a(n-30) -512304*a(n-31) +18304*a(n-32)
%e A208268 Some solutions for n=4
%e A208268 ..0..0..0..1..0..1..0....0..0..1..0..1..1..1....0..1..0..0..1..0..1
%e A208268 ..0..1..1..0..1..1..0....1..1..1..1..1..0..1....0..1..1..0..0..1..1
%e A208268 ..1..0..0..0..1..0..0....1..0..1..0..1..1..1....1..0..1..0..1..1..0
%e A208268 ..1..1..0..1..0..1..0....0..1..0..1..1..0..1....1..1..1..0..0..1..1
%K A208268 nonn
%O A208268 1,1
%A A208268 _R. H. Hardin_ Feb 24 2012