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A020883 Ordered long legs of primitive Pythagorean triangles. 38
4, 12, 15, 21, 24, 35, 40, 45, 55, 56, 60, 63, 72, 77, 80, 84, 91, 99, 105, 112, 117, 120, 132, 140, 143, 144, 153, 156, 165, 168, 171, 176, 180, 187, 195, 208, 209, 220, 221, 224, 231, 240, 247, 252, 253, 255, 260, 264, 272, 273, 275, 285, 288, 299, 304, 308, 312, 323 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Consider primitive Pythagorean triangles (A^2 + B^2 = C^2, (A, B) = 1, A < B); sequence gives values of B, sorted.

Any term in this sequence is given by f(m,n) = 2*m*n or g(m,n) = m^2 - n^2 where m and n are any two positive integers, m > 1, n < m, the greatest common divisor of m and n is 1, m and n are not both odd; e.g., f(m,n) = f(2,1) = 2*2*1 = 4. - Agola Kisira Odero, Apr 29 2016

All terms are composite. - Thomas Ordowski, Mar 12 2017

LINKS

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

Ron Knott, Pythagorean Triples and Online Calculators

MATHEMATICA

lst={}; amx=99; Do[For[b=a+1, b<(a^2/2), c=(a^2+b^2)^(1/2); If[c==IntegerPart[c]&&GCD[a, b, c]==1, AppendTo[lst, b]]; b=b+2], {a, 3, amx}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 07 2008 *)

CROSSREFS

Cf. A020882, A020884, A020885, A020886, A024354.

Sequence in context: A215011 A024353 A024354 * A002365 A212245 A046087

Adjacent sequences:  A020880 A020881 A020882 * A020884 A020885 A020886

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Extended and corrected by David W. Wilson

STATUS

approved

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Last modified September 26 01:25 EDT 2017. Contains 292500 sequences.