a(n) = pi(phi(p(P(n)))) = A000720(A000010(A000041(A000040(n)))).

Terms

a(0) =0a(1) =1a(2) =3a(3) =4a(4) =9a(5) =25a(6) =41a(7) =39a(8) =168a(9) =462a(10) =442a(11) =1939a(12) =2571a(13) =3998a(14) =5123a(15) =17040a(16) =24853a(17) =38887a(18) =195022a(19) =183430a(20) =404386a(21) =381060a(22) =1162366a(23) =2105509a(24) =1799881a(25) =5966593a(26) =5380661a(27) =14184985a(28) =10473967a(29) =22631261