OFFSET
1,1
EXAMPLE
MAPLE
From R. J. Mathar, Apr 26 2010: (Start)
isA001358 := proc(n) numtheory[bigomega](n) = 2 ; end proc:
A176705 := proc(n) a :=0 ; for k from A007510(n) to A007510(n+1) do if isA001358(k) then a := a+1 ; end if; end do: return a ; end proc:
seq(A176705(n), n=1..120) ; (End)
MATHEMATICA
nsps[lst_]:=Module[{s=lst[[1]]+1, t=lst[[2]]-1}, Count[Range[s, t], _?(PrimeOmega[ #] == 2&)]]; With[{ip=DeleteCases[Prime[Range[200]], _?(AnyTrue[{#-2, #+2}, PrimeQ]&)]}, nsps/@Partition[ip, 2, 1]] (* The program uses the function AnyTrue from Mathematica version 10 *) (* Harvey P. Dale, Aug 13 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Apr 24 2010
EXTENSIONS
a(4), a(13), a(55) corrected by R. J. Mathar, Apr 26 2010
STATUS
approved