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A264498 Numbers n that are the product of three distinct odd primes and x^2 + y^2 = n has integer solutions. 5
1105, 1885, 2405, 2465, 2665, 3145, 3445, 3485, 3965, 4505, 4745, 5185, 5365, 5785, 5945, 6205, 6305, 6409, 6565, 7085, 7345, 7565, 7585, 7685, 8177, 8245, 8585, 8845, 8905, 9061, 9265, 9605, 9685, 9805, 10205, 10585, 10865, 11245, 11285, 11645, 11713, 11765 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The three primes are of the form 4*k + 1.

LINKS

Ray Chandler, Table of n, a(n) for n = 1..10000 (first 1000 terms from Colin Barker)

EXAMPLE

1105 is in the sequence because x^2 + y^2 = 1105 = 5*13*17 has solutions (x,y) = (4,33), (9,32), (12,31) and (23,24).

PROG

(PARI)

dop(d, nmax) = {

  my(L=List(), v=vector(d, m, 1)~, f);

  for(n=1, nmax,

    f=factorint(n);

    if(#f~==d && f[1, 1]>2 && f[, 2]==v && f[, 1]%4==v, listput(L, n))

  );

  Vec(L)

}

dop(3, 15000)

CROSSREFS

Cf. A131574, A264499.

Sequence in context: A097102 A281877 A159781 * A102924 A214017 A083738

Adjacent sequences:  A264495 A264496 A264497 * A264499 A264500 A264501

KEYWORD

nonn

AUTHOR

Colin Barker, Nov 15 2015

STATUS

approved

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Last modified August 12 04:57 EDT 2020. Contains 336436 sequences. (Running on oeis4.)