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A248836 Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 2 times 2
2, 6, 22, 96, 482, 2736, 17302, 120576, 917762, 7574016, 67354582, 642041856, 6530291042, 70589700096, 808090395862, 9766250151936, 124258689304322, 1660195646078976, 23239748527125142, 340125128186658816 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A248842

LINKS

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

EXAMPLE

Some solutions for n=6

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

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

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

..1....4....0....0....4....2....0....3....3....2....3....3....4....0....0....2

..4....0....3....4....3....4....4....0....1....5....4....2....2....2....2....4

..5....6....4....5....4....0....3....6....6....5....0....2....5....4....4....4

CROSSREFS

Sequence in context: A006871 A268699 A253948 * A351919 A328500 A180389

Adjacent sequences:  A248833 A248834 A248835 * A248837 A248838 A248839

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 15 2014

STATUS

approved

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Last modified September 28 20:34 EDT 2022. Contains 357081 sequences. (Running on oeis4.)