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A064901
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Semiprimes p1*p2 such that p2 > p1 and p2 mod p1 = 3.
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1
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65, 115, 119, 215, 217, 265, 365, 377, 413, 415, 511, 515, 517, 565, 629, 707, 779, 815, 865, 965, 1099, 1115, 1165, 1207, 1243, 1315, 1391, 1393, 1415, 1465, 1501, 1565, 1589, 1687, 1727, 1765, 1769, 1865, 1883, 1915, 1969, 1981, 2165, 2177, 2215
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OFFSET
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1,1
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COMMENTS
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The semiprimes must be squarefree, since p1 does not divide p2. - Michael De Vlieger, Apr 12 2018
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LINKS
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MATHEMATICA
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Select[Range@ 2215, And[#[[All, -1]] == {1, 1}, Mod[#2, #1] == 3 & @@ #[[All, 1]]] &@ FactorInteger[#] &] (* Michael De Vlieger, Apr 12 2018 *)
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PROG
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(Python)
from sympy import factorint
f = factorint(n)
return (sum([f[i] for i in f]) == 2) and (max(f) % min(f) == 3)
x = 1
an = []
while len(an) < n:
x += 2
(PARI) isok(n) = my(f = factor(n)); (#f~ == 2) && (vecmax(f[, 2]) < 2) && ((f[2, 1] % f[1, 1]) == 3); \\ Michel Marcus, Apr 16 2018
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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