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A186312
There appear to be at least n lower twin primes between x/2 and x for all x >= a(n).
2
11, 59, 101, 149, 179, 227, 569, 599, 641, 809, 821, 1019, 1049, 1061, 1289, 1319, 1427, 1451, 1481, 1667, 1787, 1871, 1877, 1931, 1949, 2081, 2129, 2237, 2657, 2687, 2711, 2999, 3251, 3257, 3299, 3359, 3461, 3467, 3527, 3539, 3767, 3917, 4001, 4019, 4091
OFFSET
1,1
COMMENTS
The name says "appear" because this sequence assumes that the twin prime conjecture is true. Note that every term is also a lower twin prime. This sequence for lower twin primes is like the Ramanujan primes (A104272) for the sequence of prime numbers. However, in this case, we do not know if there are an infinite number of twin primes. It appears that A001359(2n) < a(n) < A001359(4n).
CROSSREFS
Cf. A001359 (lower twin primes), A088018 (counts the lower twin primes between n-1 and 2(n-1)).
Sequence in context: A168539 A320882 A048524 * A142401 A139859 A217114
KEYWORD
nonn
AUTHOR
T. D. Noe, Feb 17 2011
STATUS
approved