A183778 Half the number of (n+1)X6 binary arrays with no 2X2 subblock having exactly 2 ones

217, 1969, 15887, 136843, 1146964, 9764363, 82573675, 701022093, 5941108591, 50402814448, 427394109663, 3625210947353, 30744778516059, 260766196940447, 2211608594540996, 18757714441639535, 159090037814462703

Offset

1,1

Comments

Column 5 of A183782

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=4*a(n-1)+94*a(n-2)-260*a(n-3)-3104*a(n-4)+6922*a(n-5)+48854*a(n-6)-94118*a(n-7)-411428*a(n-8)+687376*a(n-9)+1991983*a(n-10)-2792826*a(n-11)-5747356*a(n-12)+6404184*a(n-13)+9882208*a(n-14)-8117120*a(n-15)-9774592*a(n-16)+5218304*a(n-17)+5062656*a(n-18)-1310720*a(n-19)-1048576*a(n-20)

Example

Some solutions with a(1,1)=0 for 3X6
..0..0..1..0..0..0....0..0..0..1..0..1....0..0..1..0..0..0....0..0..1..0..1..0
..0..0..0..0..0..0....0..0..0..0..0..0....1..0..0..0..0..1....1..0..0..0..0..0
..0..0..1..0..1..0....1..0..1..0..0..1....0..0..0..0..1..1....1..1..0..0..0..1

Crossrefs

Sequence in context: A262052 A020251 A320715 * A250448 A221427 A086026

Adjacent sequences: A183775 A183776 A183777 * A183779 A183780 A183781

Keyword

nonn

Author

R. H. Hardin Jan 07 2011

Status

approved