%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_
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