

A092576


a(n) = the least number which is the average of two consecutive primes and has exactly n prime factors (counted with multiplicity).


1



4, 12, 56, 72, 64, 192, 960, 1152, 3840, 7168, 4096, 30720, 36864, 110592, 360448, 663552, 2064384, 786432, 3932160, 5242880, 9437184, 63700992, 138412032, 169869312, 436207616, 3875536896, 1358954496, 1879048192, 10066329600, 8053063680, 14495514624
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OFFSET

2,1


COMMENTS

The sequence is nonmonotonic: a(6)<a(5), a(12)<a(11), a(19)<a(18).


LINKS



EXAMPLE

a(3)=12 because 12=(11+13)/2 and 12=2*2*3 has 3 prime factors.


MATHEMATICA

Flatten[With[{m=Mean/@Partition[Prime[Range[2, 370000]], 2, 1]}, Table[ Select[ m, PrimeOmega[#]==n&, 1], {n, 2, 20}]]] (* To generate 30 rather than 20 terms of the sequence, change 370000 to 458000000 and 20 to 30. *) (* Harvey P. Dale, Jun 22 2013 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



