A203383 - OEIS

%I #5 Mar 31 2012 12:36:56

%S 1,7,49,252,1519,11585,86156,606221,4325033,31601858,230910283,

%T 1678821743,12222650420,89226320509,651653318187,4758063707123,

%U 34749854417031,253886944760666,1855215535222434,13557207303083137

%N Number of nX2 0..6 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors

%C Column 2 of A203389

%H R. H. Hardin, <a href="/A203383/b203383.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 28*a(n-1) -357*a(n-2) +2947*a(n-3) -18592*a(n-4) +94955*a(n-5) -401184*a(n-6) +1451988*a(n-7) -4590176*a(n-8) +12768384*a(n-9) -31951051*a(n-10) +72039820*a(n-11) -147425146*a(n-12) +278988578*a(n-13) -478122096*a(n-14) +772651010*a(n-15) -1140165206*a(n-16) +1561997938*a(n-17) -2078573014*a(n-18) +2309819561*a(n-19) -2991164305*a(n-20) +2465714727*a(n-21) -3427669017*a(n-22) +1906150182*a(n-23) -2939880630*a(n-24) +1350797248*a(n-25) -1313333555*a(n-26) +1690232897*a(n-27) +1046282076*a(n-28) +2849146517*a(n-29) +3075606987*a(n-30) +3774538533*a(n-31) +3807731593*a(n-32) +3631581833*a(n-33) +3191721534*a(n-34) +2593241832*a(n-35) +1979588333*a(n-36) +1403683196*a(n-37) +935210902*a(n-38) +582152845*a(n-39) +339405509*a(n-40) +185220493*a(n-41) +94342890*a(n-42) +44863967*a(n-43) +19830162*a(n-44) +8128055*a(n-45) +3075933*a(n-46) +1067442*a(n-47) +337750*a(n-48) +96306*a(n-49) +24424*a(n-50) +5412*a(n-51) +1012*a(n-52) +153*a(n-53) +17*a(n-54) +a(n-55)

%e Some solutions for n=4

%e ..6..6....0..0....1..1....3..3....0..0....2..2....5..5....6..6....4..4....4..4

%e ..6..6....1..1....5..5....3..3....6..6....2..2....5..5....6..6....4..4....4..4

%e ..5..5....1..1....5..5....3..3....6..6....3..3....5..5....5..5....6..6....1..1

%e ..1..1....0..0....5..5....1..1....1..1....3..3....5..5....0..0....6..6....1..1

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 01 2012