Any digit d in the sequence says: "I am part of an integer in which you'll find d digits d".

Terms

a(0) =1a(1) =22a(2) =122a(3) =212a(4) =221a(5) =333a(6) =1333a(7) =3133a(8) =3313a(9) =3331a(10) =4444a(11) =14444a(12) =22333a(13) =23233a(14) =23323a(15) =23332a(16) =32233a(17) =32323a(18) =32332a(19) =33223a(20) =33232a(21) =33322a(22) =41444a(23) =44144a(24) =44414a(25) =44441a(26) =55555a(27) =122333a(28) =123233a(29) =123323