Position of n-th 6 in A031018.

Terms

a(0) =11a(1) =25a(2) =39a(3) =40a(4) =42a(5) =44a(6) =57a(7) =78a(8) =99a(9) =110a(10) =113a(11) =116a(12) =119a(13) =120a(14) =141a(15) =162a(16) =183a(17) =185a(18) =188a(19) =191a(20) =204a(21) =225a(22) =246a(23) =257a(24) =260a(25) =263a(26) =266a(27) =267a(28) =288a(29) =309