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A067024 Smallest prime p such that p+2 has n distinct prime-factors. 7
2, 13, 103, 1153, 15013, 255253, 4849843, 111546433, 4360010653, 100280245063, 5245694198743, 152125131763603, 7149881192889433, 421842990380476663, 16294579238595022363 (list; graph; refs; listen; history; text; internal format)
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

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Last modified January 15 18:48 EST 2019. Contains 319170 sequences. (Running on oeis4.)