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 A371256 #16 Mar 17 2024 15:10:48
%S A371256 0,1,1,2,3,2,2,2,3,4,5,5,6,7,6,5,5,4,4,5,5,5,4,5,6,6,7,8,9,9,10,11,10,
%T A371256 10,10,11,12,13,13,14,15,14,13,13,12,11,10,10,10,11,10,9,9,8,8,9,9,10,
%U A371256 11,10,10,10,11,11,10,10,9,8,9,10,10,11,12,13,13
%N A371256 The run lengths transform of the ternary expansion of n corresponds to the run lengths transform of the binary expansion of a(n).
%C A371256 For any v >= 0, the value v appears 2^A005811(v) times in the sequence.
%H A371256 Rémy Sigrist, <a href="/A371256/b371256.txt">Table of n, a(n) for n = 0..6561</a>
%F A371256 a(A005823(n)) = n - 1.
%F A371256 a(A005836(n)) = n - 1.
%F A371256 a(A004488(n)) = a(n).
%F A371256 abs(a(n+1) - a(n)) <= 1.
%e A371256 The first terms, alongside the ternary expansion of n and the binary expansion of a(n), are:
%e A371256 n a(n) ter(n) bin(a(n))
%e A371256 -- ---- ------ ---------
%e A371256 0 0 0 0
%e A371256 1 1 1 1
%e A371256 2 1 2 1
%e A371256 3 2 10 10
%e A371256 4 3 11 11
%e A371256 5 2 12 10
%e A371256 6 2 20 10
%e A371256 7 2 21 10
%e A371256 8 3 22 11
%e A371256 9 4 100 100
%e A371256 10 5 101 101
%e A371256 11 5 102 101
%e A371256 12 6 110 110
%e A371256 13 7 111 111
%e A371256 14 6 112 110
%e A371256 15 5 120 101
%o A371256 (PARI) a(n) = { my (r = [], d, l, v = 0); while (n, d = n%3; l = 0; while ((n%3)==d, n\=3; l++;); r = concat(l, r);); for (k = 1, #r, v = (v+k%2)*2^r[k]-k%2); v }
%Y A371256 See A371263 for a similar sequence.
%Y A371256 Cf. A004488, A005811, A005823, A005836, A101211, A166242, A371257.
%K A371256 nonn,base,easy
%O A371256 0,4
%A A371256 _Rémy Sigrist_, Mar 16 2024