A252427 - OEIS

%I #6 May 25 2024 21:13:56

%S 915,688,914,1801,2993,6164,13139,26670,55677,119785,248291,522400,

%T 1128516,2346628,4950707,10715161,22309343,47111547,102054851,

%U 212611950,449193290,973471926,2028637174,4287035224,9292670275,19367979783

%N Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 2 4 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 2 4 6 or 7.

%C Column 2 of A252433.

%H R. H. Hardin, <a href="/A252427/b252427.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 16*a(n-3) -74*a(n-6) +146*a(n-9) -294*a(n-12) +336*a(n-15) -316*a(n-18) +290*a(n-21) -119*a(n-24) +11*a(n-27) +6*a(n-30) -a(n-33) for n>37.

%e Some solutions for n=4

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

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

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

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

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

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

%Y Cf. A252433.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 17 2014