cp's OEIS Frontend

A248462 Number of length 1+2 0..n arrays with no three consecutive terms having the sum of any two elements equal to twice the third.

%I A248462 #8 Nov 08 2018 19:08:58
%S A248462 6,18,48,96,174,282,432,624,870,1170,1536,1968,2478,3066,3744,4512,
%T A248462 5382,6354,7440,8640,9966,11418,13008,14736,16614,18642,20832,23184,
%U A248462 25710,28410,31296,34368,37638,41106,44784,48672,52782,57114,61680,66480,71526
%N A248462 Number of length 1+2 0..n arrays with no three consecutive terms having the sum of any two elements equal to twice the third.
%H A248462 R. H. Hardin, <a href="/A248462/b248462.txt">Table of n, a(n) for n = 1..210</a>
%F A248462 Empirical: a(n) = 3*a(n-1) -2*a(n-2) -2*a(n-3) +3*a(n-4) -a(n-5).
%F A248462 Empirical for n mod 12 = 0: a(n) = n^3 + (3/2)*n^2 + 2*n.
%F A248462 Empirical for n mod 12 = 1: a(n) = n^3 + (3/2)*n^2 + 2*n + (3/2).
%F A248462 Empirical g.f.: 6*x*(1 + x^2) / ((1 - x)^4*(1 + x)). - _Colin Barker_, Nov 08 2018
%e A248462 Some solutions for n=6:
%e A248462 ..2....1....4....6....5....3....0....5....4....4....0....6....0....4....4....2
%e A248462 ..1....5....4....1....6....4....1....5....2....1....6....3....6....2....6....5
%e A248462 ..4....2....0....1....0....1....3....6....5....4....4....6....6....2....1....3
%Y A248462 Row 1 of A248461.
%K A248462 nonn
%O A248462 1,1
%A A248462 _R. H. Hardin_, Oct 06 2014