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A022004
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Initial members of prime triples (p, p+2, p+6).
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78
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5, 11, 17, 41, 101, 107, 191, 227, 311, 347, 461, 641, 821, 857, 881, 1091, 1277, 1301, 1427, 1481, 1487, 1607, 1871, 1997, 2081, 2237, 2267, 2657, 2687, 3251, 3461, 3527, 3671, 3917, 4001, 4127, 4517, 4637, 4787, 4931, 4967, 5231, 5477
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OFFSET
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1,1
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COMMENTS
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LINKS
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MAPLE
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if n= 1 then
5;
else
for a from procname(n-1)+2 by 2 do
if isprime(a) and isprime(a+2) and isprime(a+6) then
return a;
end if;
end do:
end if;
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MATHEMATICA
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Transpose[Select[Partition[Prime[Range[1000]], 3, 1], Differences[#]=={2, 4}&]][[1]] (* Harvey P. Dale, Dec 24 2011 *)
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PROG
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(Magma) [ p: p in PrimesUpTo(10000) | IsPrime(p+2) and IsPrime(p+6) ] // Vincenzo Librandi, Nov 19 2010
(Python)
from sympy import primerange
def aupto(limit):
p, q, alst = 2, 3, []
for r in primerange(5, limit+7):
if p+2 == q and p+6 == r: alst.append(p)
p, q = q, r
return alst
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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