A216988 Number of city-block distance 1, pressure limit 2 movements in an nX5 array with each element moving exactly one horizontally or vertically, no element acquiring more than two neighbors, and without 2-loops

0, 436, 83304, 15836932, 2891592224, 524266454832, 94821314531592, 17138656649477498, 3097157052139827164, 559661504116914345352, 101130124206092104688984, 18273998071786696959934276

Offset

1,2

Comments

Column 5 of A216991

Links

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

Formula

Empirical: a(n) = 290*a(n-1) -22675*a(n-2) +478832*a(n-3) +11967437*a(n-4) -564530386*a(n-5) +3207559710*a(n-6) +117049051378*a(n-7) -1758690649141*a(n-8) +2527019692944*a(n-9) +90039669736121*a(n-10) -448141227787816*a(n-11) -1334890687722822*a(n-12) +12715270269020058*a(n-13) -2815609036002122*a(n-14) -144870547164226306*a(n-15) +221033298720491173*a(n-16) +667645957791851066*a(n-17) -1724943568963877266*a(n-18) -725945588274507562*a(n-19) +4650214816610557197*a(n-20) -1213996640160911250*a(n-21) -5669124679534252729*a(n-22) +3122886613169938080*a(n-23) +3208571175520412875*a(n-24) -2065301404657189360*a(n-25) -917356595778259428*a(n-26) +484511090220075226*a(n-27) +108058347186257656*a(n-28) -26554542744326242*a(n-29) +9625145449157007*a(n-30) +1305619210151248*a(n-31) -1262955874509802*a(n-32) -74364955737456*a(n-33) +29482673821354*a(n-34) +3242530886024*a(n-35) -224842425064*a(n-36) -10270846944*a(n-37) -6291907936*a(n-38) +286480496*a(n-39) +8521768*a(n-40) +28704*a(n-41) -48*a(n-42)

Example

Some solutions for n=3 (movement: 0=n 1=e 2=s 3=w)
..1..2..2..3..2....1..1..2..3..3....1..2..3..3..3....1..1..2..2..2
..1..2..1..1..2....2..3..3..0..3....1..2..0..3..0....1..1..2..2..3
..1..1..0..3..3....1..0..3..3..0....0..3..3..1..0....1..0..3..3..0

Crossrefs

Sequence in context: A283928 A278176 A243233 * A190828 A084293 A237939

Adjacent sequences: A216985 A216986 A216987 * A216989 A216990 A216991

Keyword

nonn

Author

R. H. Hardin Sep 21 2012

Status

approved