This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A297777 #4 Feb 03 2018 16:38:12
%S A297777 1,1,1,1,1,1,1,1,2,1,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,2,1,2,2,2,2,
%T A297777 2,2,2,2,2,1,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,
%U A297777 2,1,2,2,2,2,2,2,2,2,2,1,2,2,3,3,3,3
%N A297777 Number of distinct runs in base-9 digits of n.
%C A297777 Every positive integers occurs infinitely many times. See A297770 for a guide to related sequences.
%H A297777 Clark Kimberling, <a href="/A297777/b297777.txt">Table of n, a(n) for n = 1..10000</a>
%e A297777 6643 in base-9: 1,0,1,0,1; five runs, of which 2 are distinct, so that a(6643) = 2.
%t A297777 b = 9; s[n_] := Length[Union[Split[IntegerDigits[n, b]]]]
%t A297777 Table[s[n], {n, 1, 200}]
%Y A297777 Cf. A043561 (number of runs, not necessarily distinct), A297770.
%K A297777 nonn,base,easy
%O A297777 1,9
%A A297777 _Clark Kimberling_, Jan 29 2018