cp's OEIS Frontend

A255996 Number of length n+5 0..1 arrays with at most one downstep in every n consecutive neighbor pairs.

%I A255996 #7 Jan 26 2018 06:15:44
%S A255996 64,128,188,256,337,428,530,644,771,912,1068,1240,1429,1636,1862,2108,
%T A255996 2375,2664,2976,3312,3673,4060,4474,4916,5387,5888,6420,6984,7581,
%U A255996 8212,8878,9580,10319,11096,11912,12768,13665,14604,15586,16612,17683,18800
%N A255996 Number of length n+5 0..1 arrays with at most one downstep in every n consecutive neighbor pairs.
%C A255996 Row 5 of A255992.
%H A255996 R. H. Hardin, <a href="/A255996/b255996.txt">Table of n, a(n) for n = 1..210</a>
%F A255996 Empirical: a(n) = (1/6)*n^3 + (5/2)*n^2 + (145/3)*n + 12 for n>3.
%F A255996 Empirical g.f.: x*(64 - 128*x + 60*x^2 + 16*x^3 - 7*x^4 - 8*x^5 + 4*x^6) / (1 - x)^4. - _Colin Barker_, Jan 26 2018
%e A255996 Some solutions for n=4:
%e A255996 ..1....0....0....0....1....0....0....0....1....1....0....0....0....0....1....0
%e A255996 ..1....0....0....1....1....1....0....0....1....0....1....1....0....0....1....1
%e A255996 ..1....1....1....1....1....1....1....1....1....0....1....1....1....0....0....0
%e A255996 ..1....0....1....1....1....0....0....0....1....0....0....0....1....0....0....1
%e A255996 ..1....0....0....1....0....1....1....1....1....0....0....0....0....0....0....1
%e A255996 ..1....0....1....1....0....1....1....1....1....0....0....1....0....1....0....1
%e A255996 ..0....0....1....0....0....1....1....1....0....1....0....1....0....0....0....1
%e A255996 ..0....0....1....1....1....1....1....0....0....1....1....1....0....0....1....1
%e A255996 ..1....1....0....1....0....1....1....1....0....1....0....0....0....1....0....0
%Y A255996 Cf. A255992.
%K A255996 nonn
%O A255996 1,1
%A A255996 _R. H. Hardin_, Mar 13 2015