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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
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
Sequence in context: A217368 A359343 A097282 * A249230 A250897 A366512
KEYWORD
nonn
AUTHOR
Colin Barker, Nov 15 2015
STATUS
approved