a(n) is twice the smallest k such that A051686(k) = prime(n).

Terms

a(0) =2a(1) =4a(2) =38a(3) =16a(4) =170a(5) =72a(6) =446a(7) =58a(8) =512a(9) =282a(10) =178a(11) =148a(12) =758a(13) =856a(14) =836a(15) =1592a(16) =1712a(17) =388a(18) =1906a(19) =2606a(20) =2034a(21) =1918a(22) =656a(23) =5924a(24) =1648a(25) =13082a(26) =652a(27) =1514a(28) =2758a(29) =10922