A224645 Number of (n+2)X4 0..1 matrices with each 3X3 subblock having the same population

1280, 2688, 5696, 12320, 31232, 80160, 209216, 587424, 1660544, 4729760, 13842944, 40629408, 119599040, 355446048, 1057577216, 3150294560, 9416112512, 28157621280, 84241395776, 252347085984, 756062793344, 2265711086240

Offset

1,1

Comments

Column 2 of A224651

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -3*a(n-2) +36*a(n-3) -144*a(n-4) +108*a(n-5) -503*a(n-6) +2012*a(n-7) -1509*a(n-8) +3480*a(n-9) -13920*a(n-10) +10440*a(n-11) -12564*a(n-12) +50256*a(n-13) -37692*a(n-14) +22464*a(n-15) -89856*a(n-16) +67392*a(n-17) -15552*a(n-18) +62208*a(n-19) -46656*a(n-20)

Example

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

Crossrefs

Sequence in context: A251784 A234315 A251783 * A237953 A237236 A090006

Adjacent sequences: A224642 A224643 A224644 * A224646 A224647 A224648

Keyword

nonn

Author

R. H. Hardin Apr 13 2013

Status

approved