cp's OEIS Frontend

A255995 Number of length n+4 0..1 arrays with at most one downstep in every n consecutive neighbor pairs.

%I A255995 #7 Jan 25 2018 14:09:55
%S A255995 32,64,100,144,196,257,328,410,504,611,732,868,1020,1189,1376,1582,
%T A255995 1808,2055,2324,2616,2932,3273,3640,4034,4456,4907,5388,5900,6444,
%U A255995 7021,7632,8278,8960,9679,10436,11232,12068,12945,13864,14826,15832,16883,17980
%N A255995 Number of length n+4 0..1 arrays with at most one downstep in every n consecutive neighbor pairs.
%C A255995 Row 4 of A255992.
%H A255995 R. H. Hardin, <a href="/A255995/b255995.txt">Table of n, a(n) for n = 1..210</a>
%F A255995 Empirical: a(n) = (1/6)*n^3 + 2*n^2 + (143/6)*n + 6 for n>2.
%F A255995 Empirical g.f.: x*(32 - 64*x + 36*x^2 - 4*x^4 + x^5) / (1 - x)^4. - _Colin Barker_, Jan 25 2018
%e A255995 Some solutions for n=4:
%e A255995 ..0....1....1....1....0....1....1....1....0....1....1....0....0....1....0....0
%e A255995 ..0....1....0....1....1....1....0....0....1....0....0....0....0....0....0....1
%e A255995 ..0....1....0....0....0....0....0....0....1....0....0....0....0....1....1....0
%e A255995 ..0....0....0....0....0....1....1....0....1....1....0....1....0....1....0....0
%e A255995 ..0....0....0....1....1....1....1....0....0....1....1....1....0....1....0....1
%e A255995 ..0....0....0....1....1....1....1....0....0....1....0....0....1....1....0....1
%e A255995 ..0....0....0....0....0....1....0....0....0....1....1....0....0....1....0....1
%e A255995 ..1....1....0....0....1....1....0....1....1....1....1....0....0....1....1....0
%Y A255995 Cf. A255992.
%K A255995 nonn
%O A255995 1,1
%A A255995 _R. H. Hardin_, Mar 13 2015