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A220529 Equals two maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, vertical and antidiagonal neighbors in a random 0..3 nX2 array 2
1, 6, 27, 107, 461, 1844, 7502, 29893, 119342, 473933, 1881751, 7461042, 29575992, 117195951, 464344817, 1839594735, 7287640647, 28869446541, 114362678138, 453029324891, 1794595194945, 7108951540013, 28160738630498, 111553241825416 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A220532

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) -5*a(n-2) -18*a(n-3) +24*a(n-4) -3*a(n-5) +a(n-6) -49*a(n-7) +113*a(n-8) +136*a(n-9) -407*a(n-10) +376*a(n-11) +261*a(n-12) -819*a(n-13) -157*a(n-14) +1276*a(n-15) -1095*a(n-16) -1063*a(n-17) +566*a(n-18) +423*a(n-19) -11368*a(n-20) +9391*a(n-21) -15574*a(n-22) -8963*a(n-23) +1529*a(n-24) -27108*a(n-25) +1001*a(n-26) -32699*a(n-27) -41186*a(n-28) +30586*a(n-29) -143578*a(n-30) +53047*a(n-31) -116139*a(n-32) +389*a(n-33) -37253*a(n-34) -146288*a(n-35) +52769*a(n-36) -111475*a(n-37) -122524*a(n-38) +42899*a(n-39) -163248*a(n-40) +149127*a(n-41) -118651*a(n-42) -49351*a(n-43) +76302*a(n-44) -57124*a(n-45) -7405*a(n-46) +26959*a(n-47) -45252*a(n-48) +27865*a(n-49) -8493*a(n-50) -2541*a(n-51) +10641*a(n-52) -4206*a(n-53) -595*a(n-54) +3901*a(n-55) -2258*a(n-56) +316*a(n-57) +784*a(n-58) -793*a(n-59) +318*a(n-60) -22*a(n-61) -63*a(n-62) +41*a(n-63) -18*a(n-64) +a(n-65)

EXAMPLE

Some solutions for n=3

..1..1....0..0....0..1....0..1....1..1....1..1....0..1....0..0....0..0....0..0

..0..0....1..1....0..0....1..0....1..1....0..0....0..0....0..1....0..0....1..0

..0..0....1..0....1..1....0..0....1..1....1..0....1..0....1..0....1..0....1..0

CROSSREFS

Sequence in context: A005325 A099623 A119852 * A027471 A305780 A037695

Adjacent sequences:  A220526 A220527 A220528 * A220530 A220531 A220532

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 15 2012

STATUS

approved

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Last modified July 28 07:35 EDT 2021. Contains 346321 sequences. (Running on oeis4.)