cp's OEIS Frontend

A072643 Half of the binary width of the terms of A014486, the number of digits in A063171(n)/2.

%I A072643 #27 Feb 18 2024 01:34:15
%S A072643 0,1,2,2,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,
%T A072643 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,6,6,6,
%U A072643 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6
%N A072643 Half of the binary width of the terms of A014486, the number of digits in A063171(n)/2.
%H A072643 Paolo Xausa, <a href="/A072643/b072643.txt">Table of n, a(n) for n = 0..10000</a>
%F A072643 Sum_{n>=1} (-1)^(n+1)/a(n) = Sum_{n>=1} (-1)^(n+1)/(2^n-1) = 0.76449978034844420919... . - _Amiram Eldar_, Feb 18 2024
%t A072643 a[n_] := Module[{i, c, a}, i = c = 0; a = 1; While[n>c, a *= (4*i+2)/(i+2); i++; c += a]; i];
%t A072643 Table[a[n], {n, 0, 104}] (* _Jean-François Alcover_, Dec 26 2017, from Sage code *)
%t A072643 Flatten[Array[Table[#, CatalanNumber[#]]&, 7, 0]] (* _Paolo Xausa_, Feb 13 2024 *)
%o A072643 (Sage)
%o A072643 def A072643(n) :
%o A072643     i = c = 0; a = 1
%o A072643     while n > c :
%o A072643         a *= (4*i+2)/(2+i)
%o A072643         i += 1; c += a
%o A072643     return i
%o A072643 [A072643(n) for n in (0..100)] # _Peter Luschny_, Sep 07 2012
%Y A072643 Each value v occurs A000108(v) times. The maximum position for value v to occur is A014138(v). Permutations: A071673, A072644, A072645, A072660. Cf. also A002024, A072649.
%K A072643 nonn,base
%O A072643 0,3
%A A072643 _Antti Karttunen_, Jun 02 2002