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A072643 Half of the binary width of the terms of A014486, the number of digits in A063171(n)/2. 37

%I #27 Feb 18 2024 01:34:15

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

%H Paolo Xausa, <a href="/A072643/b072643.txt">Table of n, a(n) for n = 0..10000</a>

%F 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 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 Table[a[n], {n, 0, 104}] (* _Jean-François Alcover_, Dec 26 2017, from Sage code *)

%t Flatten[Array[Table[#, CatalanNumber[#]]&, 7, 0]] (* _Paolo Xausa_, Feb 13 2024 *)

%o (Sage)

%o def A072643(n) :

%o i = c = 0; a = 1

%o while n > c :

%o a *= (4*i+2)/(2+i)

%o i += 1; c += a

%o return i

%o [A072643(n) for n in (0..100)] # _Peter Luschny_, Sep 07 2012

%Y 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 nonn,base

%O 0,3

%A _Antti Karttunen_, Jun 02 2002

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Last modified March 29 07:27 EDT 2024. Contains 371265 sequences. (Running on oeis4.)