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Search: id:A103246
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| A103246 |
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Numbers y, without duplication, in pythagorean triples x,y,z where x,y,z are relatively prime composite numbers. |
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+0
2
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| 21, 27, 33, 55, 57, 63, 75, 77, 81, 87, 91, 93, 99, 105, 111, 115, 117, 119, 123, 125, 129, 133, 135, 143, 147, 153, 155, 161, 165, 171, 177, 183, 185, 187, 189, 195, 201, 203, 207, 213, 215, 217, 219, 225, 235, 237, 243, 247, 249, 253, 255, 259, 265, 267, 273
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The example is the smallest such triple in terms of x. In terms of y, 220^2 + 21^2 = 221^2 is the smallest such triple.
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LINKS
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MathForFun, Title?
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EXAMPLE
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x=16,y=63, 16^2 + 63^2 = 65^2. 63 is the 6-th entry in the list.
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PROGRAM
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(PARI) pythtri(n) = { local(a, b, c=0, k, x, y, z, vy, j); w = vector(n*n); for(a=1, n, for(b=1, n, x=2*a*b; y=b^2-a^2; z=b^2+a^2; if(y > 0 &!isprime(x) &!isprime(y) &!isprime(z), if(gcd(x, y)==1&gcd(x, z)==1&gcd(y, z)==1, c++; w[c]=y; ) ) ) ); vy=vector(c); w=vecsort(w); for(j=1, n*n, if(w[j]>0, k++; vy[k]=w[j]; ) ); for(j=1, 200, if(vy[j+1]<>vy[j], print1(vy[j]", ")) ) }
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CROSSREFS
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Sequence in context: A035700 A134935 A064507 this_sequence A072392 A098898 A098768
Adjacent sequences: A103243 A103244 A103245 this_sequence A103247 A103248 A103249
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Mar 19 2005
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