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

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, 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, 3, 3, 3, 3, 1, 2, 1, 3, 1, 1, 2, 2, 3, 2, 2, 3, 4, 3, 3, 2, 3, 2

Offset

1,5

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

a(n) <= min(a(4*n+k): 0 <= k < 4). [Reinhard Zumkeller, Jul 31 2011]

Maple

LPS:= proc(L) local nL, n, i;
  nL:= nops(L);
  for n from nL to 1 by -1 do
    for i from 1 to nL-n+1 do
      if L[i..i+n-1] = ListTools:-Reverse(L[i..i+n-1]) then return n fi
  od od:
end proc:
seq(LPS(convert(n, base, 4)), n=1..100); # Robert Israel, Dec 17 2020

Crossrefs

Cf. A050430, A050431, A050433.

Sequence in context: A043278 A125238 A025896 * A343747 A334925 A247090

Adjacent sequences: A050429 A050430 A050431 * A050433 A050434 A050435

Keyword

nonn,base

Author

Clark Kimberling

Status

approved