A226711 Number of nX2 (-1,0,1) arrays of determinants of 2X2 subblocks of some (n+1)X3 binary array

9, 71, 427, 2393, 13691, 80043, 469273, 2739433, 15958607, 93008549, 542420159, 3163594535, 18448581619, 107577118339, 627315001045, 3658138216921, 21332152588333, 124396206594399, 725402407325709, 4230105619473679

Offset

1,1

Comments

Column 2 of A226717

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +4*a(n-2) +43*a(n-3) +198*a(n-4) +625*a(n-5) +1567*a(n-6) +3202*a(n-7) +5151*a(n-8) +6414*a(n-9) +6021*a(n-10) +4065*a(n-11) +1737*a(n-12) +216*a(n-13) -252*a(n-14) -168*a(n-15) -36*a(n-16)

Example

Some solutions for n=3
.-1..0....0..1...-1..0....1.-1...-1..1....1..0...-1..0....0.-1....0..0....1..0
..0..0...-1..0....0.-1...-1..0....1.-1...-1..0....1..0....1..1....1..1....0..0
.-1..0...-1..0....1..1....0.-1....0..1....0.-1....1..1....0..0....0..1...-1.-1

Crossrefs

Sequence in context: A231419 A227848 A226846 * A231420 A081900 A164551

Adjacent sequences: A226708 A226709 A226710 * A226712 A226713 A226714

Keyword

nonn

Author

R. H. Hardin Jun 15 2013

Status

approved