cp's OEIS Frontend

A330740 a(n) = min(n, A004488(n)), where A004488(n) is base-3 sum n+n without carries.

%I A330740 #7 Jan 11 2020 21:50:11
%S A330740 0,1,1,3,4,5,3,5,4,9,10,11,12,13,14,15,16,17,9,11,10,15,17,16,12,14,
%T A330740 13,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,
%U A330740 49,50,51,52,53,27,29,28,33,35,34,30,32,31,45,47,46,51,53,52,48,50,49,36,38,37,42,44,43,39,41,40,81
%N A330740 a(n) = min(n, A004488(n)), where A004488(n) is base-3 sum n+n without carries.
%C A330740 After the initial zero, sequence contains only terms of A132141, each appearing exactly twice.
%H A330740 Antti Karttunen, <a href="/A330740/b330740.txt">Table of n, a(n) for n = 0..59048</a>
%F A330740 a(n) = min(n, A004488(n)).
%o A330740 (PARI) A330740(n) = min(n,subst(Pol(apply(x->(3-x)%3, digits(n, 3)), 'x), 'x, 3));
%Y A330740 Cf. A004488, A132141.
%Y A330740 Central diagonal of A325825 (after the initial zero).
%K A330740 nonn,base
%O A330740 0,4
%A A330740 _Antti Karttunen_, Jan 11 2020