Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #14 Aug 30 2021 01:47:55
%S 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 41,42,44,45,47,16,50,51,53,54,56,19,59,60,62,21,65,22,68,69,71,72,74,
%U 25,77,78,80,27,83,28,86,87,89,30,92,31,95
%N a(n) = (1/2)*s(n), where s(n) is the n-th even number in A026177.
%C 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 Michael De Vlieger, <a href="/A026214/b026214.txt">Table of n, a(n) for n = 1..10000</a>
%F From _Kevin Ryde_, Feb 29 2020: (Start)
%F 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 a(n) = A026177(ceiling(3n/2))/2.
%F (End)
%o (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 Cf. A026177.
%K nonn
%O 1,1
%A _Clark Kimberling_