Least k such that A038025(k)=n-th composite number or 0 if none.

Terms

a(0) =5a(1) =184613a(2) =67a(3) =10a(4) =11a(5) =13a(6) =127a(7) =77a(8) =33a(9) =191a(10) =187a(11) =22a(12) =23a(13) =25a(14) =26a(15) =1337a(16) =28a(17) =3909a(18) =504511a(19) =37a(20) =43a(21) =57a(22) =36a(23) =4331a(24) =39a(25) =83a(26) =441