

A067024


Smallest prime p such that p+2 has n distinct primefactors.


7



2, 13, 103, 1153, 15013, 255253, 4849843, 111546433, 4360010653, 100280245063, 5245694198743, 152125131763603, 7149881192889433, 421842990380476663, 16294579238595022363
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..15.


FORMULA

a(n) = Min_{p; A001221(p+2) = n}.


EXAMPLE

For n = 1,...,7 the factors of 2+a(n) are as follows: 2*2, 3*5, 3*5*7, 3*5*7*11, 3*5*7*11*13, 3*5*7*11*13*17, 3*5*7*11*13*17*19; i.e., a(n) = A002110(n+1)/2 which is prime for n = 2,...,7.


CROSSREFS

Cf. A001221, A002110, A053705, A067023.
Sequence in context: A007809 A259146 A103513 * A083062 A204261 A127746
Adjacent sequences: A067021 A067022 A067023 * A067025 A067026 A067027


KEYWORD

nonn


AUTHOR

Labos Elemer, Dec 29 2001


EXTENSIONS

a(8)a(15) from Donovan Johnson, Jan 21 2009


STATUS

approved



