A043278 - OEIS

%I #19 Sep 20 2023 17:56:48

%S 1,1,1,1,2,1,1,1,1,2,1,1,1,1,2,2,1,1,1,2,3,2,2,1,1,2,1,1,1,1,2,2,1,1,

%T 1,1,2,1,1,2,2,3,2,1,1,1,2,2,1,1,1,1,2,1,1,1,1,2,1,2,2,2,3,3,2,2,2,1,

%U 2,1,1,1,1,2,1,1,1,1,2,2,2,2,2,3,4,3,3,2,2,2

%N Maximal run length in base 4 representation of n.

%C Sequences A031942 (or A043090), A037977, A037978, A037979 list numbers for which a(n)=1, a(n)=2, a(n)=3, a(n)=4. - _M. F. Hasler_, Jul 23 2013

%H Winston de Greef, <a href="/A043278/b043278.txt">Table of n, a(n) for n = 1..10000</a>

%p mRunLen := proc(L)

%p     if nops(L) = 0 then

%p         0;

%p     else

%p         a := 1 ;

%p         for i from 2 to nops(L) do

%p             if op(i,L) = op(i-1,L) then

%p                 a := a+1 ;

%p             else

%p                 a := max(a, procname([op(i..nops(L),L)])) ;

%p                 break;

%p             end if;

%p         end do:

%p         a ;

%p     end if ;

%p end proc:

%p A043278 := proc(n)

%p     convert(n,base,4) ;

%p     mRunLen(%) ;

%p end proc: # _R. J. Mathar_, Jul 26 2015

%t Table[Max[Length/@Split[IntegerDigits[n,4]]],{n,100}] (* _Harvey P. Dale_, Jan 21 2014 *)

%o (PARI) A043278(n, b=4)={my(m,c=1); while(n>0, n%b==(n\=b)%b && c++ && next; m=max(m, c); c=1); m} \\ _M. F. Hasler_, Jul 23 2013

%Y Cf. A043276-A043290 for base-2 to base-16 analogs.

%K nonn,base

%O 1,5

%A _Clark Kimberling_