cp's OEIS Frontend

A254211 Number of length n 1..(1+2) arrays with no leading or trailing partial sum equal to a prime and no consecutive values equal.

%I A254211 #21 Jan 27 2015 17:45:42
%S A254211 1,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
%T A254211 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,18,456,2178,3376,2222,
%U A254211 720,158,24,0,0,0,0,0,10,122,204,116,26,2,10,72,84,25,6,4,0,0,0,0,0
%N A254211 Number of length n 1..(1+2) arrays with no leading or trailing partial sum equal to a prime and no consecutive values equal.
%C A254211 These are vectors [u_1 ... u_n] such that
%C A254211 (i)   u_i = 1,2 or 3,
%C A254211 (ii)  u_i != u_{i+1},
%C A254211 (iii) Sum_{i=1..k} u_i != prime for k=1..n,
%C A254211 (iv)  Sum_{i=k..n} u_i != prime for k=1..n.
%C A254211 Conjecture: There are infinitely many n > 0 with a(n) > 0. - _Alois P. Heinz_, Jan 27 2015
%H A254211 Alois P. Heinz, <a href="/A254211/b254211.txt">Table of n, a(n) for n = 1..1970</a>
%e A254211 All solutions for n=5:
%e A254211 ..1
%e A254211 ..3
%e A254211 ..2
%e A254211 ..3
%e A254211 ..1
%Y A254211 Column k=1 of A254218.
%K A254211 nonn,look,nice
%O A254211 1,57
%A A254211 _R. H. Hardin_, Jan 26 2015