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A205921 Number of (n+1)X4 0..3 arrays with the number of clockwise edge increases in every 2X2 subblock equal to one, and every 2X2 determinant nonzero 1
1828, 15561, 67372, 583542, 2570656, 22176946, 98991836, 849405824, 3837701468, 32699583658, 149381183572, 1262924581602, 5828725185288, 48878384865034, 227757652474132, 1894271871158330, 8906948226136424, 73477236256867430 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A205926

LINKS

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

FORMULA

Empirical: a(n) = 119*a(n-2) +4*a(n-3) -5671*a(n-4) -332*a(n-5) +140502*a(n-6) +10096*a(n-7) -1946081*a(n-8) -121492*a(n-9) +14700531*a(n-10) +208884*a(n-11) -48951435*a(n-12) +4024144*a(n-13) -33808327*a(n-14) +31195156*a(n-15) +638938677*a(n-16) -621414254*a(n-17) -1072066945*a(n-18) +2389471556*a(n-19) -139848819*a(n-20) -4343451250*a(n-21) -8924971670*a(n-22) +8604001380*a(n-23) +41032270257*a(n-24) -17581883290*a(n-25) -41163594096*a(n-26) +31849234498*a(n-27) -5655121439*a(n-28) -14589728092*a(n-29) +62766122284*a(n-30) -23316251278*a(n-31) -64429104908*a(n-32) +15204624364*a(n-33) +20441413453*a(n-34) +5918648096*a(n-35) +3638449139*a(n-36) -3873731102*a(n-37) -2437649449*a(n-38) +113148320*a(n-39) +628657782*a(n-40) +146176756*a(n-41) -79826388*a(n-42) -11383360*a(n-43) +2290236*a(n-44) +1090352*a(n-45) -354504*a(n-46) -2240*a(n-47) +14112*a(n-48) for n>51

EXAMPLE

Some solutions for n=4

..1..0..1..2....3..1..3..1....3..3..0..3....0..2..2..1....1..0..2..0

..1..1..1..1....0..1..1..1....2..3..3..3....2..2..1..1....2..2..2..3

..1..2..1..3....1..1..2..3....2..2..3..1....2..1..1..2....3..1..2..2

..1..1..1..2....1..2..2..2....2..3..3..3....2..2..1..1....0..1..1..2

..2..0..1..1....1..1..2..0....2..2..3..0....0..1..1..0....1..1..2..2

CROSSREFS

Sequence in context: A167266 A177786 A235073 * A196895 A151644 A031934

Adjacent sequences:  A205918 A205919 A205920 * A205922 A205923 A205924

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 01 2012

STATUS

approved

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Last modified October 2 23:51 EDT 2022. Contains 357230 sequences. (Running on oeis4.)