A092576 a(n) = the least number which is the average of two consecutive primes and has exactly n prime factors (counted with multiplicity).

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

Offset

2,1

Comments

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

Links

Donovan Johnson, Table of n, a(n) for n = 2..300

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

Cf. A024675, A078443.

Sequence in context: A367450 A151469 A268408 * A149420 A298680 A149421

Adjacent sequences: A092573 A092574 A092575 * A092577 A092578 A092579

Keyword

nonn

Author

Zak Seidov, Feb 29 2004

Extensions

Edited by Don Reble, Mar 17 2007

Status

approved