%I #4 Dec 01 2014 19:16:51
%S 3333,49937,801579,13857083,256067697,4998606173,101704182219,
%T 2131286320259,45573675360613,987755223334609,21600165423395247,
%U 475127012597829623,10491401478930086305,232250320365109441073
%N Number of (n+1)X(4+1) 0..2 arrays with every 2X2 subblock summing to 2 4 or 6
%C Column 4 of A251335
%H R. H. Hardin, <a href="/A251331/b251331.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 111*a(n-1) -5237*a(n-2) +134729*a(n-3) -1976784*a(n-4) +14570501*a(n-5) -6257960*a(n-6) -691950920*a(n-7) +3247825564*a(n-8) +12777329879*a(n-9) -101388355602*a(n-10) -188393021686*a(n-11) +1552588774998*a(n-12) +3138186098031*a(n-13) -10631972625424*a(n-14) -29038904778576*a(n-15) +24522254457525*a(n-16) +115175966523374*a(n-17) +1433760275247*a(n-18) -228490103219515*a(n-19) -79675394560726*a(n-20) +256041689359832*a(n-21) +114826605322128*a(n-22) -180212378888064*a(n-23) -68945736471552*a(n-24) +83818696903296*a(n-25) +16742484728832*a(n-26) -24182967520512*a(n-27) +158813849088*a(n-28) +3514094493696*a(n-29) -614056771584*a(n-30) -141288800256*a(n-31) +49463820288*a(n-32) -3822059520*a(n-33)
%e Some solutions for n=2
%e ..1..0..1..1..0....1..2..2..1..1....2..0..0..2..2....1..2..0..1..2
%e ..2..1..2..0..1....2..1..1..2..2....2..2..2..0..0....0..1..1..2..1
%e ..2..1..2..0..1....1..2..0..1..1....0..0..0..2..2....2..1..1..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 01 2014