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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A165158 Hypotenuses of primitive Pythagorean triangles such that all 3 sides are composite. 3
65, 85, 125, 145, 169, 185, 205, 221, 265, 289, 305, 325, 365, 377, 425, 445, 481, 485, 493, 505, 533, 545, 565, 625, 629, 685, 689, 697, 725, 745, 785, 793, 845, 865, 901, 905, 925, 949, 965, 985, 1025, 1037, 1073, 1105, 1145, 1157, 1165, 1189, 1205, 1241 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers C in triples of the form A^2+B^2=C^2, gcd(A,B,C)=1 and all of A, B and C in A002808.

If multiple solutions exists for the same C, like for example (A,B,C) = (16,63,65) and (33,56,65),

only one instance of C is added to the sequence.

LINKS

Table of n, a(n) for n=1..50.

EXAMPLE

(A,B,C) = (16,63,65), (36,77,85), (44,117,125) etc

MATHEMATICA

lst={}; Do[Do[If[IntegerQ[a=Sqrt[c^2-b^2]]&&GCD[a, b, c]==1, If[a>=b, Break[]]; If[ !PrimeQ[a]&&!PrimeQ[b]&&!PrimeQ[c], AppendTo[lst, c]]], {b, c-1, 4, -1}], {c, 5, 2000, 1}]; Union@lst

CROSSREFS

Cf. A020882, A165159

Sequence in context: A024508 A025303 A071011 * A084648 A224770 A274044

Adjacent sequences:  A165155 A165156 A165157 * A165159 A165160 A165161

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Sep 06 2009

EXTENSIONS

Typo in description corrected by Alan Frank, Oct 09 2009

Definition clarified, comment moved to the examples and new comment added - R. J. Mathar, Oct 21 2009

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy .

Last modified July 25 12:45 EDT 2017. Contains 289795 sequences.