# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a211831 Showing 1-1 of 1 %I A211831 #4 Apr 21 2012 19:05:58 %S A211831 1,16,157,1254,9068,62617,426022,2913894,20307833,145503003, %T A211831 1077731960,8277491943,66003259942,546398875027,4692545543444, %U A211831 41760563809046,384605668021029,3660788725969481,35964832246977675,364242679197958081 %N A211831 Number of nonnegative integer arrays of length n+4 with new values 0 upwards introduced in order, no three adjacent elements equal, and containing the value 4 %C A211831 Column 3 of A211836 %H A211831 R. H. Hardin, Table of n, a(n) for n = 1..210 %e A211831 Some solutions for n=3 %e A211831 ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0 %e A211831 ..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1 %e A211831 ..2....0....0....2....2....2....1....2....2....0....2....2....2....2....2....0 %e A211831 ..3....1....2....0....3....2....2....3....3....2....3....3....0....2....3....2 %e A211831 ..1....2....2....3....2....3....3....1....4....3....1....0....2....3....4....3 %e A211831 ..4....3....3....4....0....0....1....3....5....4....2....3....3....4....5....4 %e A211831 ..3....4....4....2....4....4....4....4....4....3....4....4....4....4....3....2 %K A211831 nonn %O A211831 1,2 %A A211831 _R. H. Hardin_ Apr 21 2012 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE