cp's OEIS Frontend

A255997 Number of length n+6 0..1 arrays with at most one downstep in every n consecutive neighbor pairs.

%I A255997 #7 Jan 26 2018 06:15:34
%S A255997 128,256,354,451,568,705,854,1016,1192,1383,1590,1814,2056,2317,2598,
%T A255997 2900,3224,3571,3942,4338,4760,5209,5686,6192,6728,7295,7894,8526,
%U A255997 9192,9893,10630,11404,12216,13067,13958,14890,15864,16881,17942,19048,20200
%N A255997 Number of length n+6 0..1 arrays with at most one downstep in every n consecutive neighbor pairs.
%C A255997 Row 6 of A255992.
%H A255997 R. H. Hardin, <a href="/A255997/b255997.txt">Table of n, a(n) for n = 1..210</a>
%F A255997 Empirical: a(n) = (1/6)*n^3 + 3*n^2 + (533/6)*n + 28 for n>4.
%F A255997 Empirical g.f.: x*(128 - 256*x + 98*x^2 + 59*x^3 - 8*x^4 - 21*x^5 - 8*x^6 + 9*x^7) / (1 - x)^4. - _Colin Barker_, Jan 26 2018
%e A255997 Some solutions for n=4:
%e A255997 ..0....0....0....1....1....0....1....0....1....1....1....0....1....0....0....0
%e A255997 ..1....1....0....1....1....1....1....1....0....1....0....1....0....0....0....0
%e A255997 ..0....0....0....0....0....0....1....0....0....0....0....1....0....1....1....0
%e A255997 ..0....0....1....0....0....0....1....0....0....0....0....0....0....1....1....0
%e A255997 ..1....1....0....0....0....1....1....1....1....0....0....0....0....0....0....0
%e A255997 ..1....1....0....0....0....1....1....1....1....0....1....0....0....0....0....1
%e A255997 ..0....0....0....0....0....1....1....1....1....0....0....1....1....0....1....1
%e A255997 ..1....0....0....0....0....1....0....0....1....1....1....1....1....1....1....1
%e A255997 ..1....1....0....0....0....1....1....0....1....1....1....0....0....1....0....1
%e A255997 ..1....1....0....1....0....1....1....0....0....1....1....0....1....0....1....0
%Y A255997 Cf. A255992.
%K A255997 nonn
%O A255997 1,1
%A A255997 _R. H. Hardin_, Mar 13 2015