a(1)=1; thereafter, if n even, a(n) = a(n-1)-st prime, and if n odd, a(n) = a(n-1)-st nonprime.

A280028

a(1)=1; thereafter, if n even, a(n) = a(n-1)-st prime, and if n odd, a(n) = a(n-1)-st nonprime.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =7a(4) =12a(5) =37a(6) =52a(7) =239a(8) =301a(9) =1993a(10) =2338a(11) =20753a(12) =23356a(13) =266587a(14) =291968a(15) =4134187a(16) =4446630a(17) =75947059a(18) =80652283a(19) =1625456353a(20) =1710094788a(21) =39954587527a(22) =41737658509

External references