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 A044879 #9 Sep 11 2021 10:47:02 %S A044879 513,514,515,516,517,518,519,521,530,539,548,557,566,575,577,578,579, %T A044879 580,581,582,583,592,593,595,596,597,598,599,600,601,602,604,605,606, %U A044879 607,608,609,610,611,613,614,615,616,617,618 %N A044879 Numbers having, in base 8, (sum of even run lengths)=(sum of odd run lengths). %o A044879 (Python) %o A044879 from itertools import groupby %o A044879 def ok(n): %o A044879 rl_sums = [0, 0] %o A044879 for k, g in groupby(oct(n)[2:]): %o A044879 rl = len(list(g)) %o A044879 rl_sums[rl%2] += rl %o A044879 return rl_sums[0] == rl_sums[1] %o A044879 print(list(filter(ok, range(619)))) # _Michael S. Branicky_, Sep 11 2021 %Y A044879 Cf. A007094. %Y A044879 Cf. A044873, A044874, A044875, A044876, A044877, A044878, A044880. %Y A044879 Cf. A044881, A044882, A044883, A044884, A044885, A044886, A044887. %K A044879 nonn,base %O A044879 1,1 %A A044879 _Clark Kimberling_