A189953 - OEIS

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A189953

1/4 the number of arrangements of 4 nonzero numbers x(i) in -n..n with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero

4, 22, 63, 159, 306, 542, 889, 1350, 1940, 2734, 3670, 4819, 6238, 7852, 9688, 11986, 14411, 17274, 20412, 23919, 27900, 32443, 37028, 42280, 48028, 54459, 60919, 68477, 76078, 84753, 93786, 103538, 113637, 125008, 136030, 149100, 162115, 176241

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Row 3 of A189951

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

EXAMPLE

Some solutions with n=3

..1....3....1....2...-2....2....3....1...-1....2...-3...-1...-3...-1....1....3

.-3...-3...-3...-2....2...-2....1....1...-1....2...-3....3....2....2...-2....3

.-3...-3....2...-2...-1....2...-3....1....1...-1...-3....2....1....1...-1...-3

..2....1...-2...-2...-1....2...-2....1...-1...-1...-1....2....3...-3....3...-1

CROSSREFS

Sequence in context: A104171 A036924 A130015 * A174814 A106846 A086863

Adjacent sequences: A189950 A189951 A189952 * A189954 A189955 A189956

KEYWORD

nonn

AUTHOR

R. H. Hardin May 02 2011

STATUS

approved