a(1)=a(2)=1. a(n+1) = a(n) + a(smallest prime dividing n).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =5a(5) =10a(6) =11a(7) =22a(8) =23a(9) =25a(10) =26a(11) =52a(12) =53a(13) =106a(14) =107a(15) =109a(16) =110a(17) =220a(18) =221a(19) =442a(20) =443a(21) =445a(22) =446a(23) =892a(24) =893a(25) =898a(26) =899a(27) =901a(28) =902a(29) =1804