cp's OEIS Frontend

A189320 Number of nondecreasing arrangements of n+2 numbers in 0..3 with the last equal to 3 and each after the second equal to the sum of one or two of the preceding four.

%I A189320 #7 Jul 22 2025 11:41:30
%S A189320 5,7,11,16,22,28,34,40,46,52,58,64,70,76,82,88,94,100,106,112,118,124,
%T A189320 130,136,142,148,154,160,166,172,178,184,190,196,202,208,214,220,226,
%U A189320 232,238,244,250,256,262,268,274,280,286,292,298,304,310,316,322,328,334,340
%N A189320 Number of nondecreasing arrangements of n+2 numbers in 0..3 with the last equal to 3 and each after the second equal to the sum of one or two of the preceding four.
%C A189320 Column 3 of A189326
%H A189320 R. H. Hardin, <a href="/A189320/b189320.txt">Table of n, a(n) for n = 1..200</a>
%F A189320 Empirical: a(n) = 6*n - 8 for n>3
%e A189320 All solutions for n=4
%e A189320 ..2....1....1....1....0....0....3....1....0....1....1....1....0....1....1....1
%e A189320 ..3....2....2....1....1....1....3....3....1....1....1....2....3....1....1....1
%e A189320 ..3....2....2....2....1....1....3....3....1....1....1....3....3....1....2....2
%e A189320 ..3....3....2....2....2....2....3....3....1....2....2....3....3....1....2....3
%e A189320 ..3....3....3....3....2....3....3....3....2....2....3....3....3....2....2....3
%e A189320 ..3....3....3....3....3....3....3....3....3....3....3....3....3....3....3....3
%K A189320 nonn
%O A189320 1,1
%A A189320 _R. H. Hardin_ Apr 20 2011