1,1

Distance between twin semiprime pairs.

Table of n, a(n) for n=1..88.

A175648 := proc(n) option remember; if n = 1 then 6; else for a from procname(n-1)+1 do if numtheory[bigomega](a) = 2 and numtheory[bigomega](a+4) = 2 then return a; end if; end do: end if; end proc:

A175668 := proc(n) A175648(n+1)-A175648(n) ; end proc:

seq(A175668(n), n=1..100) ; # R. J. Mathar, Aug 07 2010

Cf. A053319, A175612, A175648.

Sequence in context: A230024 A132150 A091389 * A113249 A087171 A282026

Adjacent sequences: A175665 A175666 A175667 * A175669 A175670 A175671

nonn

Juri-Stepan Gerasimov, Aug 05 2010

Terms from a(33) on corrected by R. J. Mathar, Aug 07 2010

approved