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A167293 Long legs of Pythagorean triangles that are not divisible by any other long leg of a Pythagorean triangle. 0
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 * A267769 A192201 A054308

Adjacent sequences:  A167290 A167291 A167292 * A167294 A167295 A167296

KEYWORD

nonn

AUTHOR

Gerald McGarvey, Nov 01 2009

EXTENSIONS

Comments and PARI program corrected by Gerald McGarvey, Nov 03 2009

STATUS

approved

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Last modified December 4 13:03 EST 2021. Contains 349526 sequences. (Running on oeis4.)