A167293 - OEIS

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A167293

Long legs of Pythagorean triangles that are not divisible by any other long leg of a Pythagorean triangle.

4, 15, 21, 35, 55, 77, 91, 99, 117, 143, 153, 171, 187, 209, 221, 247, 253, 299, 323, 325, 377, 391, 403, 425, 437, 475, 493, 527, 551, 575, 589, 621, 629, 667, 697, 703, 713, 725, 775, 779, 783, 817, 837, 851, 899, 925, 943, 957, 989, 999, 1023, 1025, 1073

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

All long legs of Pythagorean triangles (A009023) are multiples of these values, so these values can be thought of as "primes" of the sequence of long legs.

LINKS

Table of n, a(n) for n=1..53.

PROG

(PARI) llp = vector(60); np = 1; llp[np] = 4;

notdiv(k) = for(j=1, np, if(k%llp[j], 1, return(0))); return(1);

isLongLeg(n) = local(b); b=0; for(k=1, n-1, if(issquare(k^2+n^2), b=1)); return(b);

for(k=4, 1175, if(notdiv(k), if(isLongLeg(k), np+=1; llp[np]=k)))

for(n=1, 60, print1(llp[n], ", "))

CROSSREFS

A009023

Sequence in context: A297711 A055465 A209870 * A376693 A267769 A192201

Adjacent sequences: A167290 A167291 A167292 * A167294 A167295 A167296