A209731 1/4 the number of (n+1)X4 0..3 arrays with every 2X2 subblock having distinct edge sums

696, 9712, 137888, 1995752, 28927984, 420545824, 6111765608, 88883321584, 1292321119496, 18793764804064, 273281958853584, 3974120752445352, 57789976679148952, 840380963807821656, 12220602110589974744

Offset

1,1

Comments

Column 3 of A209736

Links

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

Formula

Empirical: a(n) = 14*a(n-1) +156*a(n-2) -2224*a(n-3) -7407*a(n-4) +130352*a(n-5) +139225*a(n-6) -3967738*a(n-7) -347340*a(n-8) +71434181*a(n-9) -28076530*a(n-10) -808939517*a(n-11) +497233986*a(n-12) +5937897631*a(n-13) -3990226320*a(n-14) -28600057758*a(n-15) +17484900856*a(n-16) +90252403892*a(n-17) -42280584722*a(n-18) -183177183716*a(n-19) +52345388842*a(n-20) +228997243328*a(n-21) -25762931959*a(n-22) -164559319657*a(n-23) -1566342824*a(n-24) +63269043596*a(n-25) +5091355688*a(n-26) -11482954208*a(n-27) -1243500736*a(n-28) +729105088*a(n-29) +59218432*a(n-30) -12493824*a(n-31)

Example

Some solutions for n=4
..3..1..3..3....2..2..1..0....2..3..2..2....1..1..3..3....0..1..0..0
..3..0..0..1....0..3..3..3....0..1..0..1....3..0..0..1....3..3..3..1
..1..1..2..2....0..1..2..0....2..2..0..2....2..2..3..3....1..2..0..1
..2..3..3..0....2..3..3..1....0..1..0..1....1..0..0..1....0..2..3..1
..0..1..2..0....1..1..0..1....2..2..2..3....1..3..2..2....1..2..0..0

Crossrefs

Sequence in context: A221418 A157435 A048426 * A222782 A282048 A163008

Adjacent sequences: A209728 A209729 A209730 * A209732 A209733 A209734

Keyword

nonn

Author

R. H. Hardin Mar 12 2012

Status

approved