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A089058 Numbers x such that xy/(x+y) is an integer for integers y=x,x+1,..n. 1
2, 3, 4, 4, 5, 6, 6, 6, 7, 8, 8, 8, 9, 9, 10, 10, 10, 10, 11, 12, 12, 12, 12, 12, 13, 14, 14, 14, 14, 15, 15, 15, 16, 16, 16, 16, 17, 18, 18, 18, 18, 18, 18, 19, 20, 20, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

xy/(x+y) is the side of the inscribed square of a right triangle with integer legs x and y.

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

x=20,y=5, 100/25 = integer 4.

PROG

(PARI) xydivxpy(n) = { for(x=1, n, for(y=x, n, h=x*y/(x+y); if(h==floor(h), print1(x", "); ) ) ) }

CROSSREFS

Sequence in context: A147847 A268680 A126974 * A282717 A303735 A187103

Adjacent sequences:  A089055 A089056 A089057 * A089059 A089060 A089061

KEYWORD

nonn

AUTHOR

Cino Hilliard, Dec 02 2003, corrected Nov 23 2006

STATUS

approved

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Last modified February 16 21:59 EST 2019. Contains 320200 sequences. (Running on oeis4.)