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A171179 Numbers that are divisible by exactly 3 primes (counted with multiplicity) and sandwiched between primes. 0
12, 18, 30, 42, 102, 138, 282, 618, 642, 822, 1698, 1878, 2082, 2238, 2382, 2658, 2802, 3462, 3558, 3918, 4638, 4722, 5442, 6198, 6702, 8538, 8598, 9678, 10938, 12162, 12378, 12822, 12918, 13218, 13722, 13758, 13998, 14082, 16062, 17418, 19542 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are 106 of these numbers below 100,000.

LINKS

Table of n, a(n) for n=1..41.

EXAMPLE

12=2*2*3, 11 and 13 primes,..

MATHEMATICA

Select[Range[9! ], Plus@@Last/@FactorInteger[ # ]==3&&PrimeQ[ #-1]&&PrimeQ[ #+1]&]

CROSSREFS

Cf. A014612

Equals 6*A060212. [From Zak Seidov and Esko Ranta, Dec 06 2009]

Sequence in context: A167597 A138636 A075281 * A333869 A257768 A007371

Adjacent sequences:  A171176 A171177 A171178 * A171180 A171181 A171182

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Dec 04 2009

STATUS

approved

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Last modified June 2 17:02 EDT 2020. Contains 334787 sequences. (Running on oeis4.)