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 A297784 #4 Feb 04 2018 12:42:56
%S A297784 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,
%T A297784 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,
%U A297784 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,2
%N A297784 Number of distinct runs in base-16 digits of n.
%C A297784 Every positive integers occurs infinitely many times. See A297770 for a guide to related sequences.
%H A297784 Clark Kimberling, <a href="/A297784/b297784.txt">Table of n, a(n) for n = 1..10000</a>
%e A297784 17830144 in base-16: 1,1,0,1,1,0,0; four runs, of which 3 are distinct, so that a(17830144) = 3.
%t A297784 b = 16; s[n_] := Length[Union[Split[IntegerDigits[n, b]]]]
%t A297784 Table[s[n], {n, 1, 200}]
%Y A297784 Cf. A043568 (number of runs, not necessarily distinct), A297770.
%K A297784 nonn,base,easy
%O A297784 1,16
%A A297784 _Clark Kimberling_, Feb 03 2018