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 A270200 #14 Jun 02 2016 16:16:08
%S A270200 0,1,2,4,7,8,12,13,15,16,21,22,24,25,28,29,31,32,38,39,41,42,45,46,48,
%T A270200 49,53,54,56,57,60,61,63,64,71,72,74,75,78,79,81,82,86,87,89,90,93,94,
%U A270200 96,97,102,103,105,106,109,110,112,113,117,118,120,121,124,125,127,128,136,137,139,140,143,144,146,147,151
%N A270200 a(0) = 0; for n >= 1, a(n) = A054429(A005187(1+A054429(n-1))).
%C A270200 After the initial zero, numbers that occur in the range of A233272.
%H A270200 Antti Karttunen, <a href="/A270200/b270200.txt">Table of n, a(n) for n = 0..8192</a>
%F A270200 a(0) = 0; for n >= 1, a(n) = A054429(A005187(1+A054429(n-1))).
%F A270200 Other identities. For all >= 0:
%F A270200 A233273(n) = a(n+2).
%t A270200 s = Range[2^(# + 1) - 1, 2^#, -1] & /@ Range[0, 12] // Flatten; {0, 1}~Join~Table[s[[2 # - DigitCount[2 #, 2, 1] &[1 + s[[n - 1]]]]], {n, 2, 74}] (* _Michael De Vlieger_, Jun 01 2016, after _Harvey P. Dale_ at A005187 and A054429 *)
%o A270200 (define (A270200 n) (if (zero? n) n (A054429 (A005187 (+ 1 (A054429 (- n 1)))))))
%Y A270200 Complement: A270198.
%Y A270200 Cf. A005187, A054429, A233272, A233273.
%Y A270200 Cf. also A233271 (a subsequence).
%K A270200 nonn,base
%O A270200 0,3
%A A270200 _Antti Karttunen_, May 31 2016