A203841 Number of nX3 0..3 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors

1, 16, 262, 2706, 28744, 362648, 4683983, 58985474, 742707090, 9444433515, 120525293455, 1537990623251, 19634124076530, 250858226995102, 3206685488455209, 40998751596467461, 524256086958176875

Offset

1,2

Comments

Column 3 of A203846

Links

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

Formula

Empirical: a(n) = 40*a(n-1) -721*a(n-2) +8351*a(n-3) -71744*a(n-4) +478442*a(n-5) -2531517*a(n-6) +10756674*a(n-7) -36829136*a(n-8) +101651121*a(n-9) -224247749*a(n-10) +401911276*a(n-11) -679710121*a(n-12) +1526442592*a(n-13) -4705796798*a(n-14) +13226010464*a(n-15) -27108695975*a(n-16) +32744883694*a(n-17) +8881419118*a(n-18) -136791085108*a(n-19) +337532358689*a(n-20) -483437940773*a(n-21) +269137804732*a(n-22) +433769036844*a(n-23) -1656803206918*a(n-24) +3437842999894*a(n-25) -3292192875226*a(n-26) -1072487395284*a(n-27) +9069594646357*a(n-28) -19857639419402*a(n-29) +12265933248727*a(n-30) +24548518439778*a(n-31) -44510794462917*a(n-32) +37720059523251*a(n-33) +17452394298885*a(n-34) -126293736263711*a(n-35) +55539104326036*a(n-36) +117343908822586*a(n-37) -86426762269695*a(n-38) +69084866608755*a(n-39) +117041433267182*a(n-40) -321354828898553*a(n-41) -228698389528094*a(n-42) +343033252638837*a(n-43) +205872927928340*a(n-44) -68482998480250*a(n-45) +220066801199110*a(n-46) -40264056535166*a(n-47) -715378598171906*a(n-48) -326391835848142*a(n-49) +616141720164655*a(n-50) +665315890636065*a(n-51) +15614588185630*a(n-52) -434428480448949*a(n-53) -426177921201257*a(n-54) -66058412504806*a(n-55) +298384515942894*a(n-56) +270196388622583*a(n-57) -15487136945556*a(n-58) -153277674800579*a(n-59) -85579952535636*a(n-60) +11477805337773*a(n-61) +46642386092920*a(n-62) +27275659769786*a(n-63) -4643493392307*a(n-64) -14336090083392*a(n-65) -5050091745696*a(n-66) +2580369596484*a(n-67) +2456185316788*a(n-68) +267179175091*a(n-69) -443991677680*a(n-70) -207099346909*a(n-71) +5887250032*a(n-72) +34026874910*a(n-73) +10525068419*a(n-74) -732130779*a(n-75) -1397475228*a(n-76) -381125210*a(n-77) -141273*a(n-78) +29905664*a(n-79) +9484383*a(n-80) +1106984*a(n-81) -172374*a(n-82) -102122*a(n-83) -22652*a(n-84) -3000*a(n-85) -232*a(n-86) -8*a(n-87)

Example

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

Crossrefs

Sequence in context: A264532 A240368 A204715 * A301838 A302066 A281473

Adjacent sequences: A203838 A203839 A203840 * A203842 A203843 A203844

Keyword

nonn

Author

R. H. Hardin Jan 06 2012

Status

approved