# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a270257
Showing 1-1 of 1

%I A270257 #4 Mar 14 2016 09:18:59
%S A270257 0,12,24,48,72,108,144,192,240,300,360,432,504,588,672,768,864,972,
%T A270257 1080,1200,1320,1452,1584,1728,1872,2028,2184,2352,2520,2700,2880,
%U A270257 3072,3264,3468,3672,3888,4104,4332,4560,4800,5040,5292,5544,5808,6072,6348,6624
%N A270257 Number of 2X2X2 triangular 0..n arrays with some element plus some adjacent element totalling n exactly once.
%C A270257 Row 2 of A270256.
%H A270257 R. H. Hardin, <a href="/A270257/b270257.txt">Table of n, a(n) for n = 1..210</a>
%F A270257 Empirical: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4)
%F A270257 Empirical for n mod 2 = 0: a(n) = 3*n^2
%F A270257 Empirical for n mod 2 = 1: a(n) = 3*n^2 - 3
%e A270257 Some solutions for n=4
%e A270257 ...2....3....0....3....0....1....2....1....3....0....4....3....0....4....3....2
%e A270257 ..3.2..4.0..4.1..2.2..4.3..4.0..2.1..0.3..4.1..1.4..2.0..2.1..2.2..2.2..1.4..2.0
%Y A270257 Cf. A270256.
%K A270257 nonn
%O A270257 1,2
%A A270257 _R. H. Hardin_, Mar 14 2016

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE