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A281695 Number of 3Xn 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
0, 15, 847, 14575, 172398, 1900616, 17698286, 154129813, 1275251254, 10132993005, 78117611504, 587910877987, 4338607753232, 31501834570803, 225621916093246, 1597186816890237, 11193139375201572, 77755257717795413, 535979713724257216 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Row 3 of A281693.
LINKS
FORMULA
Empirical: a(n) = 17*a(n-1) -102*a(n-2) +327*a(n-3) -1122*a(n-4) +3306*a(n-5) -6463*a(n-6) +19106*a(n-7) -17295*a(n-8) +69491*a(n-9) -5686*a(n-10) +146028*a(n-11) +128697*a(n-12) +149517*a(n-13) +324330*a(n-14) -39179*a(n-15) +190705*a(n-16) -146256*a(n-17) -775732*a(n-18) -287653*a(n-19) -61287*a(n-20) -624068*a(n-21) -190577*a(n-22) +872472*a(n-23) +455292*a(n-24) -159861*a(n-25) +323130*a(n-26) +380599*a(n-27) -313277*a(n-28) -413976*a(n-29) +16356*a(n-30) +58782*a(n-31) -94092*a(n-32) -9164*a(n-33) +96964*a(n-34) +44568*a(n-35) -23024*a(n-36) -19832*a(n-37) -672*a(n-38) +2432*a(n-39) +512*a(n-40) for n>45
EXAMPLE
Some solutions for n=4
..0..1..0..2. .0..1..1..1. .0..1..1..0. .0..1..2..0. .0..1..0..1
..0..1..1..2. .0..1..2..1. .1..2..1..2. .2..2..0..1. .0..2..2..0
..1..2..1..0. .2..2..2..1. .2..2..1..0. .1..1..2..2. .0..0..1..2
CROSSREFS
Cf. A281693.
Sequence in context: A261828 A205432 A020240 * A223276 A233019 A270962
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 27 2017
STATUS
approved

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Last modified March 29 09:59 EDT 2024. Contains 371268 sequences. (Running on oeis4.)