A251838 - OEIS

%I #4 Dec 09 2014 15:54:11

%S 974,981,641,872,1443,1951,2784,4949,7897,11384,21033,35203,50846,

%T 95287,161329,232978,438821,745265,1075374,2030079,3451785,4975148,

%U 9405623,16003305,23037002,43604345,74229499,106714968,202216349,344400871

%N Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime

%C Column 1 of A251845

%H R. H. Hardin, <a href="/A251838/b251838.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 13*a(n-3) +a(n-5) -62*a(n-6) -12*a(n-8) +140*a(n-9) +50*a(n-11) -175*a(n-12) -90*a(n-14) +127*a(n-15) +85*a(n-17) -50*a(n-18) -42*a(n-20) +8*a(n-21) +8*a(n-23) for n>28

%e Some solutions for n=4

%e ..0..1..0....2..3..1....0..3..1....3..3..3....3..1..0....3..3..3....1..3..2

%e ..3..0..3....2..1..3....3..3..0....3..0..1....0..1..0....0..1..3....0..3..1

%e ..3..0..3....0..2..2....1..3..0....0..1..0....1..2..1....1..2..3....0..0..1

%e ..0..1..0....2..1..1....0..3..1....3..0..3....3..1..0....0..1..3....1..1..2

%e ..3..0..1....2..1..1....0..3..3....3..0..3....0..1..3....3..1..0....0..0..1

%e ..3..3..3....0..2..2....1..3..0....2..0..2....1..2..3....1..2..1....0..3..1

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 09 2014