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 A320409 T(n,k)=Number of nXk 0..1 arrays with every element unequal to 0, 1, 2, 4 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 7
 1, 2, 2, 4, 6, 4, 8, 14, 14, 8, 16, 35, 47, 35, 16, 32, 95, 156, 156, 95, 32, 64, 257, 548, 786, 548, 257, 64, 128, 700, 1970, 3761, 3761, 1970, 700, 128, 256, 1907, 7049, 18725, 27236, 18725, 7049, 1907, 256, 512, 5202, 25364, 92578, 191615, 191615, 92578 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Table starts ...1....2.....4.......8.......16.........32..........64...........128 ...2....6....14......35.......95........257.........700..........1907 ...4...14....47.....156......548.......1970........7049.........25364 ...8...35...156.....786.....3761......18725.......92578........463045 ..16...95...548....3761....27236.....191615.....1353623.......9623424 ..32..257..1970...18725...191615....1957026....19677729.....199877194 ..64..700..7049...92578..1353623...19677729...282206549....4085687781 .128.1907.25364..463045..9623424..199877194..4085687781...84346447443 .256.5202.91307.2308299.68454701.2025592349.58997871413.1737667793009 LINKS R. H. Hardin, Table of n, a(n) for n = 1..199 FORMULA Empirical for column k: k=1: a(n) = 2*a(n-1) k=2: a(n) = 2*a(n-1) +3*a(n-2) -2*a(n-3) -2*a(n-4) -a(n-6) +a(n-7) k=3: [order 23] for n>25 k=4: [order 83] for n>85 EXAMPLE Some solutions for n=5 k=4 ..0..1..1..1. .0..0..0..0. .0..0..1..1. .0..0..0..0. .0..0..0..0 ..1..1..0..0. .0..1..1..0. .0..1..1..1. .0..0..1..1. .1..0..0..1 ..0..1..0..0. .1..0..0..1. .1..1..1..1. .1..0..1..1. .0..0..0..0 ..1..0..1..0. .1..1..1..1. .0..0..0..0. .0..1..0..1. .0..0..1..0 ..1..1..0..0. .1..1..0..1. .0..0..0..1. .0..0..0..1. .0..1..1..0 CROSSREFS Column 1 is A000079(n-1). Column 2 is A318018. Sequence in context: A318075 A318343 A318024 * A096466 A088965 A059474 Adjacent sequences: A320406 A320407 A320408 * A320410 A320411 A320412 KEYWORD nonn,tabl AUTHOR R. H. Hardin, Oct 12 2018 STATUS approved

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Last modified March 20 05:51 EDT 2023. Contains 361359 sequences. (Running on oeis4.)