Position of n-th 6 in A031057.

Terms

a(0) =45a(1) =47a(2) =49a(3) =51a(4) =134a(5) =137a(6) =140a(7) =143a(8) =230a(9) =233a(10) =236a(11) =239a(12) =326a(13) =329a(14) =332a(15) =335a(16) =422a(17) =425a(18) =428a(19) =431a(20) =518a(21) =521a(22) =524a(23) =527a(24) =541a(25) =544a(26) =547a(27) =550a(28) =553a(29) =556