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A037454 a(n) = Sum_{i=0..m} d(i)*6^i, where Sum_{i=0..m} d(i)*3^i is the base 3 representation of n.

%I A037454 #19 Jan 03 2021 15:38:22
%S A037454 0,1,2,6,7,8,12,13,14,36,37,38,42,43,44,48,49,50,72,73,74,78,79,80,84,
%T A037454 85,86,216,217,218,222,223,224,228,229,230,252,253,254,258,259,260,
%U A037454 264,265,266,288,289,290,294,295,296,300,301,302,432,433,434,438
%N A037454 a(n) = Sum_{i=0..m} d(i)*6^i, where Sum_{i=0..m} d(i)*3^i is the base 3 representation of n.
%H A037454 Clark Kimberling, <a href="/A037454/b037454.txt">Table of n, a(n) for n = 0..1000</a>
%F A037454 From _Peter Bala_, Dec 01 2016: (Start)
%F A037454 a(n) = n + 1/2*Sum_{k >= 1} 6^k*floor(n/3^k). Cf. A037462, A007091 and A102491.
%F A037454 a(0) = 0; a(n) = 6*a(n/3) if n == 0 (mod 3) else a(n) = a(n-1) + 1. (End)
%p A037454 seq(n + (1/2)*add(6^k*floor(n/3^k), k = 1..floor(ln(n)/ln(3))), n = 1..100); # _Peter Bala_, Dec 01 2016
%t A037454 t = Table[FromDigits[RealDigits[n, 3], 6], {n, 0, 100}]
%t A037454 (* _Clark Kimberling_, Aug 03 2012 *)
%o A037454 (Julia)
%o A037454 function a(n)
%o A037454     m, r, b = n, 0, 1
%o A037454     while m > 0
%o A037454         m, q = divrem(m, 3)
%o A037454         r += b * q
%o A037454         b *= 6
%o A037454     end
%o A037454 r end; [a(n) for n in 0:57] |> println # _Peter Luschny_, Jan 03 2021
%Y A037454 Cf. A037462, A007091, A102491.
%K A037454 nonn,base,easy
%O A037454 0,3
%A A037454 _Clark Kimberling_
%E A037454 Offset changed to 0 by _Clark Kimberling_, Aug 03 2012