a(n) = Sum_{d|n} phi(d) * prime(d).

Terms

a(0) =2a(1) =5a(2) =12a(3) =19a(4) =46a(5) =41a(6) =104a(7) =95a(8) =150a(9) =165a(10) =312a(11) =203a(12) =494a(13) =365a(14) =432a(15) =519a(16) =946a(17) =545a(18) =1208a(19) =747a(20) =990a(21) =1105a(22) =1828a(23) =991a(24) =1986a(25) =1709a(26) =2004a(27) =1663a(28) =3054a(29) =1481