

A118594


Palindromes in base 3 (written in base 3).


12



0, 1, 2, 11, 22, 101, 111, 121, 202, 212, 222, 1001, 1111, 1221, 2002, 2112, 2222, 10001, 10101, 10201, 11011, 11111, 11211, 12021, 12121, 12221, 20002, 20102, 20202, 21012, 21112, 21212, 22022, 22122, 22222, 100001, 101101, 102201, 110011
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OFFSET

1,3


COMMENTS

The number of ndigit terms is given by A225367.  M. F. Hasler, May 05 2013 [Moved here on May 08 2013]
Digitwise application of A000578 (and also superposition of a(n) with its horizontal OR vertical reflection) yields A006072.  M. F. Hasler, May 08 2013
Equivalently, palindromes k (written in base 10) such that 4*k is a palindrome.  Bruno Berselli, Sep 12 2018


LINKS

Table of n, a(n) for n=1..39.
Eric Weisstein's World of Mathematics, Palindromic Number
Eric Weisstein's World of Mathematics, Ternary


MATHEMATICA

(* get NextPalindrome from A029965 *) Select[NestList[NextPalindrome, 0, 1110], Max@IntegerDigits@# < 3 &] (* Robert G. Wilson v, May 09 2006 *)
Select[FromDigits/@Tuples[{0, 1, 2}, 8], IntegerDigits[#]==Reverse[ IntegerDigits[ #]]&] (* Harvey P. Dale, Apr 20 2015 *)


PROG

(PARI) {for(l=1, 5, u=vector((l+1)\2, i, 10^(i1)+(2*i1<l)*10^(li))~; forvec(v=vector((l+1)\2, i, [l>1&&i==1, 2]), print1(v*u", ")))} \\ The nth term could be produced by using (partial sums of) A225367 to skip all shorter terms, and then skipping the adequate number of vectors v until n is reached.  M. F. Hasler, May 08 2013
(Sage)
[int(n.str(base=3)) for n in (0..757) if Word(n.digits(3)).is_palindrome()] # Peter Luschny, Sep 13 2018


CROSSREFS

Cf. A007089, A014190, A057148, A118595, A118596, A118597, A118598, A118599, A118600, A002113.
Sequence in context: A018711 A018737 A162468 * A263720 A235609 A018351
Adjacent sequences: A118591 A118592 A118593 * A118595 A118596 A118597


KEYWORD

nonn,base,easy


AUTHOR

Martin Renner, May 08 2006


EXTENSIONS

More terms from Robert G. Wilson v, May 09 2006


STATUS

approved



