A185490 Number of (n+1) X 3 binary arrays with every 2 X 2 subblock sum equal to some horizontal or vertical neighbor 2 X 2 subblock sum.

24, 128, 708, 3792, 20872, 114724, 631720, 3480976, 19187324, 105781152, 583235304, 3215888676, 17732499352, 97778898080, 539167491548, 2973062740752, 16394019043496, 90399771851092, 498482055878472, 2748728769087488

Offset

1,1

Comments

Column 2 of A185497.

Links

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

Formula

Empirical: a(n)=8*a(n-1)-8*a(n-2)-38*a(n-3)+77*a(n-4)-304*a(n-5)+229*a(n-6)+896*a(n-7)+602*a(n-8)+3542*a(n-9)-1451*a(n-10)-1518*a(n-11)-14971*a(n-12)-30824*a(n-13)-23130*a(n-14)-25773*a(n-15)+40123*a(n-16)+73174*a(n-17)+166738*a(n-18)+101179*a(n-19)+52400*a(n-20)-160962*a(n-21)-297696*a(n-22)-442388*a(n-23)-320904*a(n-24)-33320*a(n-25)+401152*a(n-26)+681440*a(n-27)+823424*a(n-28)+439488*a(n-29)-162240*a(n-30)-562816*a(n-31)-538112*a(n-32)-225024*a(n-33)+151040*a(n-34)+199680*a(n-35)+12288*a(n-36)-36864*a(n-37).

Example

Some solutions for 4 X 3
..0..1..0....1..1..1....0..0..1....1..0..1....0..0..0....1..1..1....0..1..0
..1..1..1....0..1..1....1..0..0....1..1..1....1..1..1....1..1..1....1..1..1
..0..1..1....1..1..1....1..0..1....0..1..0....0..1..0....1..0..1....0..0..0
..1..1..1....0..0..0....0..1..0....1..0..1....1..0..1....0..1..0....0..0..0

Crossrefs

Cf. A185497.

Sequence in context: A182186 A188304 A167981 * A293365 A093699 A275405

Adjacent sequences: A185487 A185488 A185489 * A185491 A185492 A185493

Keyword

nonn

Author

R. H. Hardin, Jan 29 2011

Status

approved