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 A230302 Let M(1)=0 and for n >= 2, let B(n)=M(ceiling(n/2))+M(floor(n/2))+2, M(n)=2^B(n)+M(floor(n/2))+1; sequence gives B(n). 2

%I

%S 2,7,12,136,260,4233,8206,87112285931760246646623899502532662136846,

%T 174224571863520493293247799005065324265486,

%U 1852673427797059126777135760139006525739432040582009271277945243629142736371850,3705346855594118253554271520278013051304639509300498049262642688253220148478214

%N Let M(1)=0 and for n >= 2, let B(n)=M(ceiling(n/2))+M(floor(n/2))+2, M(n)=2^B(n)+M(floor(n/2))+1; sequence gives B(n).

%C a(n) is the leading power of 2 in M(n) = A230303(n).

%D Max A. Alekseyev, Donovan Johnson and N. J. A. Sloane, On Kaprekar's Junction Numbers, in preparation, 2017.

%H Max Alekseyev, <a href="/A230302/a230302_1.txt">Table giving values of n and an expression for a(n) for n=2..100</a>

%H <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a>

%e The terms after 8206 are 2^136+4110, 2^137+14, 2^260+2^136+136, 2^261+262, 2^4233+2^260+260, ... (see also A230303).

%p f:=proc(n) option remember; local B, M;

%p if n<=1 then RETURN([0,0]);

%p else

%p if (n mod 2) = 0 then B:=2*f(n/2)[2]+2;

%p else B:=f((n+1)/2)[2]+f((n-1)/2)[2]+2; fi;

%p M:=2^B+f(floor(n/2))[2]+1; RETURN([B,M]); fi;

%p end proc;

%p [seq(f(n)[1],n=1..7)];

%Y Cf. A228085, A230093, A230303 (for M(n)).

%K nonn

%O 2,1

%A _N. J. A. Sloane_, Oct 24 2013

%E a(11) corrected, expressions for a(2)-a(100) added by _Max Alekseyev_, Nov 02 2013

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Last modified October 20 12:47 EDT 2019. Contains 328257 sequences. (Running on oeis4.)