A226712 Number of nX3 (-1,0,1) arrays of determinants of 2X2 subblocks of some (n+1)X4 binary array

25, 427, 4671, 49019, 539703, 6045209, 67402167, 748987305, 8323819069, 92555521915, 1029235074739, 11444508108671, 127253466995703, 1414962443443107, 15733386654458777, 174944155490939157

Offset

1,1

Comments

Column 3 of A226717

Links

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

Formula

Empirical: a(n) = 6*a(n-1) +21*a(n-2) +225*a(n-3) +1298*a(n-4) +5199*a(n-5) +16766*a(n-6) +43152*a(n-7) +91435*a(n-8) +158318*a(n-9) +223398*a(n-10) +254586*a(n-11) +227455*a(n-12) +127131*a(n-13) -96068*a(n-14) -591403*a(n-15) -1621443*a(n-16) -3311084*a(n-17) -5001806*a(n-18) -4578514*a(n-19) +1244048*a(n-20) +14953574*a(n-21) +35329236*a(n-22) +55983183*a(n-23) +67517216*a(n-24) +62754397*a(n-25) +41504720*a(n-26) +11196702*a(n-27) -17169663*a(n-28) -34815254*a(n-29) -38925338*a(n-30) -32542876*a(n-31) -21565420*a(n-32) -11265912*a(n-33) -4330896*a(n-34) -899552*a(n-35) +220264*a(n-36) +315600*a(n-37) +167480*a(n-38) +57632*a(n-39) +13696*a(n-40) +2176*a(n-41) +192*a(n-42)

Example

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

Crossrefs

Sequence in context: A021944 A299845 A020499 * A020577 A021714 A056090

Adjacent sequences: A226709 A226710 A226711 * A226713 A226714 A226715

Keyword

nonn

Author

R. H. Hardin Jun 15 2013

Status

approved