cp's OEIS Frontend

A136275 Similar to A137284, but considering Sum{ k = 1,2,3,... } 5^(-nk).

%I A136275 #19 Sep 08 2022 08:45:32
%S A136275 1,2,3,5,8,12,18,26,38,55,79,114,164,235,337,483,692,991,1418,2029,
%T A136275 2903,4154,5944,8504,12167,17408,24906,35633,50980,72936,104348,
%U A136275 149289,213585,305572,437175,625457,894827,1280209,1831566,2620379,3748915
%N A136275 Similar to A137284, but considering Sum{ k = 1,2,3,... } 5^(-nk).
%H A136275 Vincenzo Librandi, <a href="/A136275/b136275.txt">Table of n, a(n) for n = 0..1000</a>
%F A136275 a(n) = ceiling( a(n-1)*log_5(10) ). - _Max Alekseyev_, May 14 2009
%e A136275 Start from 0;
%e A136275 0 + 5^(-1) = 0.2;
%e A136275 0.2 + 5^(-2) = 0.24 (first digit "2" is equal to the previous number's digit after the decimal point);
%e A136275 0.24 + 5^(-3) = 0.248 (first digits "24" are equal to the previous number's digits after the decimal point);
%e A136275 0.248 + 5^(-5) = 0.24832 (first digits "248" are equal to the previous number's digits after the decimal point);
%e A136275 etc.
%t A136275 Join[{1}, a=1; a=Table[a=Ceiling[a Log[5, 10]], {n, 40}]] (* _Vincenzo Librandi_, Jul 05 2019 *)
%o A136275 (Magma) [n eq 1 select 1 else Ceiling(Self(n-1)*Log(5,10)): n in [1..50]]; // _Vincenzo Librandi_, Jul 05 2019
%K A136275 nonn,base,easy
%O A136275 0,2
%A A136275 _Paolo P. Lava_ and _Giorgio Balzarotti_, Mar 19 2008
%E A136275 Extended by _Max Alekseyev_, May 14 2009