login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A065607 Related to reciprocal Pythagorean triples: 1/a(n)^2 + 1/k^2 = 1/j^2 has an integer solution (k,j) with k<a(n). 3
20, 40, 60, 80, 100, 120, 140, 156, 160, 180, 200, 220, 240, 255, 260, 280, 300, 312, 320, 340, 360, 380, 400, 420, 440, 460, 468, 480, 500, 510, 520, 540, 560, 580, 600, 600, 609, 620, 624, 640, 660, 680, 700, 720, 740, 760, 765, 780, 780, 800, 820, 840 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

COMMENTS

The entries 600 and 780 occur in two solutions each; the others entries uniquely.

MAPLE

a := []; for n from 2 to 1000 do for m from 2 to n do if (numer(simplify(1/n^2+1/m^2))=1) then if type(sqrt(denom(simplify(1/n^2+1/m^2))), integer)=true then print(n, m, ifactor(n), ifactor(m), ifactor(denom(simplify(1/n^2+1/m^2))), sqrt(denom(simplify(1/n^2+1/m^2)))); printlevel := -1; a := [op(a), n]; printlevel := 1 fi fi od od; print(a);

CROSSREFS

Sequence in context: A046794 A104153 A049057 * A008602 A061830 A041790

Adjacent sequences:  A065604 A065605 A065606 * A065608 A065609 A065610

KEYWORD

nonn

AUTHOR

Len Smiley (smiley(AT)math.uaa.alaska.edu), Dec 01 2001

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 15 23:53 EST 2012. Contains 205860 sequences.