

A082276


Smallest number whose digits can be permuted to get exactly n distinct palindromes.


0




OFFSET

1,2


COMMENTS

Note that 10^n + 1 is always an upper bound.
a(12) = 1000122, a(18) = 10000122, a(30) = 10012233; probably a(24) = 11223344. Any number C(i+j,j) is the number of palindromes from 2i 1's and 2j 2's, so in particular a(10) <= 1111112222 and a(15) <= 111111112222. If a number in this sequence has an odd number of digits, the odd digit must be 0 or 1, with all other digits in pairs; if the number of digits is even, all must be in pairs. The counts of the nonzero digits must be monotonically decreasing (i.e., at least as many 1's as 2's, etc.)  Franklin T. AdamsWatters, Oct 26 2006


LINKS

Table of n, a(n) for n=1..9.


EXAMPLE

101 gives two palindromes 101 and 011 = 11 hence a(2) = 101.
a(6) = 112233, The digit permutation gives six palindromes 123321,132231,213312,231132,312213,321123.


CROSSREFS

Cf. A082274, A082275.
Sequence in context: A242138 A171764 A164842 * A069597 A139535 A139536
Adjacent sequences: A082273 A082274 A082275 * A082277 A082278 A082279


KEYWORD

base,more,nonn


AUTHOR

Amarnath Murthy, Apr 13 2003


EXTENSIONS

More terms from Franklin T. AdamsWatters, Oct 26 2006


STATUS

approved



