Position of n-th 4 in A031111.

Terms

a(0) =7a(1) =23a(2) =27a(3) =36a(4) =38a(5) =48a(6) =60a(7) =68a(8) =78a(9) =79a(10) =98a(11) =108a(12) =113a(13) =114a(14) =154a(15) =162a(16) =169a(17) =194a(18) =228a(19) =231a(20) =234a(21) =274a(22) =278a(23) =280a(24) =300a(25) =302a(26) =331a(27) =334a(28) =335a(29) =339