cp's OEIS Frontend

A230289 Let m = n-th number not divisible by 3 (A001651); a(n) = position of m in A065075, or -1 if never appears in A065075.

%I A230289 #9 Jul 31 2017 12:58:09
%S A230289 1,3,4,7,6,5,8,9,10,13,24,41,26,51,64,151,276,335,446,219,550,451,
%T A230289 1674,1685,2192,2667,9220,17647,3972,9221,17648,25311,35776,25339,
%U A230289 147018,112397,146972,212667,243892,243871,963024,1263521,1838078,2380569,2380378
%N A230289 Let m = n-th number not divisible by 3 (A001651); a(n) = position of m in A065075, or -1 if never appears in A065075.
%C A230289 It is believed that a(n) is always > 0.
%H A230289 Lars Blomberg, <a href="/A230289/b230289.txt">Table of n, a(n) for n = 1..86</a>
%H A230289 <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a>
%p A230289 read transforms; M:=100000; sp:=1; a:=[sp]; s:=sp;
%p A230289 for n from 2 to M do sp:=digsum(s); a:=[op(a),sp]; s:=s+sp; od:
%p A230289 b:=[]:
%p A230289 for n from 1 to 100 do
%p A230289 if (n mod 3) <> 0 then
%p A230289 if member(n,a,'p') then b:=[op(b),p] else b:=[op(b),-1]; fi;
%p A230289 fi;
%p A230289 od:
%p A230289 b;
%Y A230289 Cf. A065075, A001651.
%K A230289 nonn,base
%O A230289 1,2
%A A230289 _N. J. A. Sloane_, Oct 17 2013
%E A230289 a(35)-a(45) from _Lars Blomberg_, Jul 31 2017