a(n)=k-n where prime(k) is the smallest prime greater than prime(n)*prime(n+1).

Terms

a(0) =3a(1) =5a(2) =9a(3) =18a(4) =30a(5) =42a(6) =60a(7) =77a(8) =113a(9) =145a(10) =179a(11) =229a(12) =262a(13) =293a(14) =353a(15) =430a(16) =487a(17) =545a(18) =622a(19) =671a(20) =737a(21) =826a(22) =916a(23) =1052a(24) =1184a(25) =1249a(26) =1310a(27) =1373a(28) =1443a(29) =1654