A176406 Odd semiprimes minus 2.

7, 13, 19, 23, 31, 33, 37, 47, 49, 53, 55, 63, 67, 75, 83, 85, 89, 91, 93, 109, 113, 117, 119, 121, 127, 131, 139, 141, 143, 153, 157, 159, 167, 175, 181, 183, 185, 199, 201, 203, 207, 211, 213, 215, 217, 219, 233, 235, 245, 247, 251, 257, 263, 265, 285, 287

Offset

1,1

Links

Table of n, a(n) for n=1..56.

Formula

a(n) = A046315(n) - 2.

Maple

isA001358 := proc(n) numtheory[bigomega](n) = 2 ; end proc: for n from 1 to 400 by 2 do if isA001358(n+2) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, Apr 20 2010

Mathematica

Select[Range[9, 301, 2], PrimeOmega[#]==2&]-2 (* Harvey P. Dale, May 11 2018 *)

Crossrefs

Cf. A007921.

Sequence in context: A309649 A088982 A354460 * A033561 A227030 A049591

Adjacent sequences: A176403 A176404 A176405 * A176407 A176408 A176409

Keyword

nonn

Author

Juri-Stepan Gerasimov, Apr 16 2010

Extensions

Entries checked by R. J. Mathar, Apr 20 2010

Status

approved