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A120644 Area common to integer-sided isosceles triangles (x,x,y) and (x,x,z=y+2d), sorted on x > z/2, d being positive. 1
12, 60, 120, 168, 420, 420, 360, 1260, 660, 1848, 1008, 2640, 2772, 1092, 3120, 4680, 1980, 5460, 1680, 5148, 9240, 3432, 2448, 7140, 11220, 14280, 8580, 3420, 15912, 10032, 15960, 5460, 20748, 15708, 23940, 4620, 13260, 21840, 25080, 8160, 23712 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

x=A020882(n); y=2*A046086(n); z=2*A046087(n); d=A120682(n). y is twice the height of the other triangle with z as base and conversely.

Take the n-th primitive Pythagorean triple (x, y, z) ordered by increasing z, then y. (1/x)^2 + (1/y)^2 = (z/w)^2, where a(n) = w. - Ivan N. Ianakiev, Jan 12 2020

LINKS

Table of n, a(n) for n=1..41.

FORMULA

a(n) = y*z/4 = A046086(n)*A046087(n) = 2*A120734(n).

EXAMPLE

168 in the sequence refers to the area common to both triangle (25,25,14) and triangle (25,25,48).

CROSSREFS

Sequence in context: A097191 A273691 A094807 * A099829 A099830 A158443

Adjacent sequences:  A120641 A120642 A120643 * A120645 A120646 A120647

KEYWORD

easy,nonn

AUTHOR

Lekraj Beedassy, Aug 17 2006, Aug 20 2006

STATUS

approved

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Last modified April 9 13:50 EDT 2020. Contains 333352 sequences. (Running on oeis4.)