Position of n-th 6 in A031045.

Terms

a(0) =6a(1) =20a(2) =36a(3) =52a(4) =68a(5) =84a(6) =89a(7) =91a(8) =93a(9) =95a(10) =97a(11) =99a(12) =100a(13) =101a(14) =103a(15) =116a(16) =138a(17) =162a(18) =186a(19) =210a(20) =234a(21) =258a(22) =265a(23) =268a(24) =271a(25) =274a(26) =277a(27) =280a(28) =282a(29) =283