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A264499 Numbers n that are the product of four distinct odd primes and x^2 + y^2 = n has integer solutions. 4
32045, 40885, 45305, 58565, 67405, 69745, 77285, 80665, 91205, 98345, 98605, 99905, 101065, 107185, 111605, 114985, 120445, 124865, 127465, 128945, 130645, 137605, 141245, 146705, 150365, 151385, 162565, 164645, 166685, 167765, 173485, 175565, 179945, 182845 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The four 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

32045 is in the sequence because x^2 + y^2 = 32045 = 5*13*17*29 has solutions (x,y) = (2,179), (19,178), (46,173), (67,166), (74,163), (86,157), (109,142) and (122,131).

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(4, 200000)

CROSSREFS

Cf. A131574, A264498.

Sequence in context: A156977 A217368 A097282 * A249230 A250897 A146896

Adjacent sequences:  A264496 A264497 A264498 * A264500 A264501 A264502

KEYWORD

nonn

AUTHOR

Colin Barker, Nov 15 2015

STATUS

approved

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Last modified August 12 05:33 EDT 2020. Contains 336438 sequences. (Running on oeis4.)