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A203841 Number of nX3 0..3 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors 1
1, 16, 262, 2706, 28744, 362648, 4683983, 58985474, 742707090, 9444433515, 120525293455, 1537990623251, 19634124076530, 250858226995102, 3206685488455209, 40998751596467461, 524256086958176875 (list; graph; refs; listen; history; text; internal format)
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

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Last modified November 27 09:19 EST 2021. Contains 349365 sequences. (Running on oeis4.)