Position of n-th 4 in A030604.

Terms

a(0) =12a(1) =19a(2) =27a(3) =31a(4) =33a(5) =34a(6) =46a(7) =47a(8) =61a(9) =71a(10) =73a(11) =78a(12) =79a(13) =92a(14) =96a(15) =105a(16) =115a(17) =116a(18) =127a(19) =128a(20) =131a(21) =132a(22) =137a(23) =138a(24) =140a(25) =141a(26) =152a(27) =165a(28) =168a(29) =185