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

Offset: 1

Author

Gerald McGarvey, Nov 01 2009

Keywords

• nonn

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.

Crossrefs

A009023

Programs

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],", "))

Extensions

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