# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a256814 Showing 1-1 of 1 %I A256814 #7 Jan 24 2018 09:30:02 %S A256814 120,229,442,856,1656,3204,6192,11955,23088,44617,86226,166620,321960, %T A256814 622104,1202016,2322567,4487848,8671757,16756074,32377024,62560664, %U A256814 120883084,233577104,451331323,872088416,1685098737,3256043394 %N A256814 Number of length n+6 0..1 arrays with at most two downsteps in every 6 consecutive neighbor pairs. %C A256814 Column 6 of A256816. %H A256814 R. H. Hardin, Table of n, a(n) for n = 1..210 %F A256814 Empirical: a(n) = 2*a(n-1) -a(n-2) +2*a(n-3) -a(n-4) +3*a(n-6) -2*a(n-7) -6*a(n-9) +4*a(n-10). %F A256814 Empirical g.f.: x*(120 - 11*x + 104*x^2 - 39*x^3 + 48*x^4 + 93*x^5 - 190*x^6 - 128*x^7 - 250*x^8 + 252*x^9) / ((1 - x)*(1 - x - 2*x^3 - x^4 - x^5 - 4*x^6 - 2*x^7 - 2*x^8 + 4*x^9)). - _Colin Barker_, Jan 24 2018 %e A256814 Some solutions for n=4: %e A256814 ..1....1....0....0....1....1....1....0....1....0....1....1....0....0....0....0 %e A256814 ..1....0....1....0....0....1....0....1....0....0....0....0....0....1....0....0 %e A256814 ..1....0....0....1....0....1....0....1....1....0....0....0....0....0....1....1 %e A256814 ..0....0....1....1....1....1....0....0....1....1....0....1....1....0....1....0 %e A256814 ..1....0....1....1....0....0....0....0....0....0....1....0....1....0....0....1 %e A256814 ..1....1....1....1....1....1....0....0....1....0....0....0....0....0....1....0 %e A256814 ..1....0....1....0....1....1....0....1....1....0....0....1....0....1....0....0 %e A256814 ..1....1....0....1....0....1....0....0....1....1....1....1....1....0....0....0 %e A256814 ..0....0....0....0....0....0....0....1....0....0....0....1....1....0....1....1 %e A256814 ..1....0....1....1....0....0....0....0....1....0....0....1....1....1....1....0 %Y A256814 Cf. A256816. %K A256814 nonn %O A256814 1,1 %A A256814 _R. H. Hardin_, Apr 10 2015 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE