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A218288 T(n,k)=Hilltop maps: number of nXk binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or vertical neighbor in a random 0..4 nXk array 9
1, 3, 3, 7, 15, 7, 15, 63, 63, 15, 31, 255, 511, 255, 31, 61, 1019, 4091, 4091, 1019, 61, 121, 4073, 32739, 65507, 32739, 4073, 121, 241, 16289, 261905, 1048307, 1048307, 261905, 16289, 241, 481, 65153, 2095233, 16772877, 33549827, 16772877, 2095233 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Table starts

....1........3..........7............15.............31..............61

....3.......15.........63...........255...........1019............4073

....7.......63........511..........4091..........32739..........261905

...15......255.......4091.........65507........1048307........16772877

...31.....1019......32739.......1048307.......33549827......1073597617

...61.....4073.....261905......16772877.....1073597617.....68710447465

..121....16289....2095233.....268366049....34355128651...4397469258389

..241....65153...16761837....4293856057..1099364046509.281438014358653

..481...260609..134094563...68701687597.35179647135791

..961..1042417.1072755573.1099226869621

.1921..4169595.8582037499

.3839.16678079

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..97

FORMULA

Empirical: Column k=1 for an underlying 0..z array: a(n) = sum(i=1..2z+1){a(n-i)} z=1,2,3,4

EXAMPLE

Some solutions for n=3 k=4

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

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

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

CROSSREFS

Sequence in context: A218196 A218372 A218242 * A056420 A030069 A004043

Adjacent sequences:  A218285 A218286 A218287 * A218289 A218290 A218291

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Oct 25 2012

STATUS

approved

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Last modified January 17 03:10 EST 2022. Contains 350377 sequences. (Running on oeis4.)