A265511 a(n) = largest base-3 palindrome m <= n such that every base-3 digit of m is <= the corresponding digit of n; m is written in base 10.

0, 1, 2, 0, 4, 4, 0, 4, 8, 0, 10, 10, 0, 13, 13, 0, 16, 16, 0, 10, 20, 0, 13, 23, 0, 16, 26, 0, 28, 28, 0, 28, 28, 0, 28, 28, 0, 28, 28, 0, 40, 40, 0, 40, 40, 0, 28, 28, 0, 40, 40, 0, 52, 52, 0, 28, 56, 0, 28, 56, 0, 28, 56, 0, 28, 56, 0, 40, 68, 0, 40, 68, 0, 28, 56, 0, 40, 68, 0, 52, 80, 0, 82, 82, 0, 82, 82, 0, 82

Offset

0,3

Links

Robert Israel, Table of n, a(n) for n = 0..10000

Maple

F:= proc(n) local L;
  L:= convert(n, base, 3);
  if L[1] = 0 then return 0 fi;
  add(min(L[i], L[-i])*3^(i-1), i=1..nops(L))
end proc:
map(F, [$0..100]); # Robert Israel, Jan 13 2020

Crossrefs

Sequences related to palindromic floor and ceiling: A175298, A206913, A206914, A261423, A262038, and the large block of consecutive sequences beginning at A265509.

Sequence in context: A366282 A364258 A307658 * A081236 A338896 A182059

Adjacent sequences: A265508 A265509 A265510 * A265512 A265513 A265514

Keyword

nonn,base,look

Author

N. J. A. Sloane, Dec 09 2015

Status

approved