Numbers whose maximal base-10 run length is 4.

Terms

a(0) =1111a(1) =2222a(2) =3333a(3) =4444a(4) =5555a(5) =6666a(6) =7777a(7) =8888a(8) =9999a(9) =10000a(10) =11110a(11) =11112a(12) =11113a(13) =11114a(14) =11115a(15) =11116a(16) =11117a(17) =11118a(18) =11119a(19) =12222a(20) =13333a(21) =14444a(22) =15555a(23) =16666a(24) =17777a(25) =18888a(26) =19999a(27) =20000a(28) =21111a(29) =22220