cp's OEIS Frontend

A050432 Length of longest palindromic subword of (n base 4).

%I A050432 #13 Dec 17 2020 14:27:06
%S A050432 1,1,1,1,2,1,1,1,1,2,1,1,1,1,2,2,3,1,1,2,3,2,2,1,3,2,1,1,3,1,2,2,1,3,
%T A050432 1,1,2,3,1,2,2,3,2,1,1,3,2,2,1,1,3,1,2,1,3,1,1,2,3,2,2,2,3,3,4,2,2,3,
%U A050432 3,3,3,3,1,2,1,3,1,1,2,2,3,2,2,3,4,3,3,2,3,2
%N A050432 Length of longest palindromic subword of (n base 4).
%H A050432 Robert Israel, <a href="/A050432/b050432.txt">Table of n, a(n) for n = 1..10000</a>
%F A050432 a(n) <= min(a(4*n+k): 0 <= k < 4). [_Reinhard Zumkeller_, Jul 31 2011]
%p A050432 LPS:= proc(L) local nL,n,i;
%p A050432   nL:= nops(L);
%p A050432   for n from nL to 1 by -1 do
%p A050432     for i from 1 to nL-n+1 do
%p A050432       if L[i..i+n-1] = ListTools:-Reverse(L[i..i+n-1]) then return n fi
%p A050432   od od:
%p A050432 end proc:
%p A050432 seq(LPS(convert(n,base,4)),n=1..100); # _Robert Israel_, Dec 17 2020
%Y A050432 Cf. A050430, A050431, A050433.
%K A050432 nonn,base
%O A050432 1,5
%A A050432 _Clark Kimberling_