A206123 Number of (n+1)X4 0..2 arrays with every 2X2 subblock having nonzero determinant and having the same number of clockwise edge increases as its horizontal and vertical neighbors

558, 3692, 25340, 201498, 1622095, 13475116, 112183711, 939358762, 7868519564, 65979083372, 553282676669, 4640551430206, 38922156734987, 326466825617358, 2738306512199386, 22968242764669498, 192652048790354377

Offset

1,1

Comments

Column 3 of A206128

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 6*a(n-1) +72*a(n-2) -352*a(n-3) -1842*a(n-4) +8483*a(n-5) +22782*a(n-6) -111329*a(n-7) -146524*a(n-8) +887675*a(n-9) +408834*a(n-10) -4451798*a(n-11) +555841*a(n-12) +13452774*a(n-13) -6983392*a(n-14) -21422904*a(n-15) +14294732*a(n-16) +15409732*a(n-17) -5535750*a(n-18) -954280*a(n-19) -7463176*a(n-20) -9198940*a(n-21) +4005472*a(n-22) +6349224*a(n-23) +1754032*a(n-24) -47088*a(n-25) -288592*a(n-26) -493376*a(n-27) -708032*a(n-28) -195872*a(n-29) +160192*a(n-30) +95296*a(n-31) +10752*a(n-32) -5376*a(n-33) for n>37

Example

Some solutions for n=4
..2..2..1..2....1..1..2..1....2..1..2..2....1..2..0..1....1..1..1..1
..1..2..2..2....1..2..2..2....2..2..2..1....2..0..1..2....2..1..2..0
..2..2..1..2....2..2..1..2....1..2..1..1....2..1..2..0....2..2..2..2
..2..1..1..1....2..1..1..1....2..2..2..0....1..2..0..1....2..1..2..0
..2..2..1..2....1..1..2..0....2..0..2..2....0..1..2..2....2..2..2..2

Crossrefs

Sequence in context: A071393 A352350 A253290 * A253160 A253478 A253483

Adjacent sequences: A206120 A206121 A206122 * A206124 A206125 A206126

Keyword

nonn

Author

R. H. Hardin Feb 04 2012

Status

approved