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 A026214 #14 Aug 30 2021 01:47:55 %S A026214 2,1,5,6,8,3,11,4,14,15,17,18,20,7,23,24,26,9,29,10,32,33,35,12,38,13, %T A026214 41,42,44,45,47,16,50,51,53,54,56,19,59,60,62,21,65,22,68,69,71,72,74, %U A026214 25,77,78,80,27,83,28,86,87,89,30,92,31,95 %N A026214 a(n) = (1/2)*s(n), where s(n) is the n-th even number in A026177. %C A026214 The even values in A026177 are A026177(3n) = 2n or 6n, and A026177(3n+2) = 6n+4. The odd values are A026177(3n+1) = 2n+1. So a(2n) = A026177(3n)/2 and a(2n+1) = A026177(3n+2)/2. The latter is always the "small" case in A026177. The former is A026177(3n) big or small according to the lowest non-0 ternary digit of 3n, and consequently the formula below for a(n). - _Kevin Ryde_, Feb 29 2020 %H A026214 Michael De Vlieger, <a href="/A026214/b026214.txt">Table of n, a(n) for n = 1..10000</a> %F A026214 From _Kevin Ryde_, Feb 29 2020: (Start) %F A026214 a(n) = n/2 if n even and A060236(n)=2, otherwise a(n) = ceiling(3n/2), where A060236(n) is the lowest non-0 ternary digit of n. %F A026214 a(n) = A026177(ceiling(3n/2))/2. %F A026214 (End) %o A026214 (PARI) a(n) = if(n%2 || (n/3^valuation(n,3))%3==1, ceil(3*n/2), n/2); \\ _Kevin Ryde_, Feb 29 2020 %Y A026214 Cf. A026177. %K A026214 nonn %O A026214 1,1 %A A026214 _Clark Kimberling_