This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A072643 Half of the binary width of the terms of A014486, the number of digits in A063171(n)/2. 30

%I

%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.

%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 *)

%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

%O 0,3

%A _Antti Karttunen_, Jun 02 2002

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 20 20:55 EST 2019. Contains 320345 sequences. (Running on oeis4.)