The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS"). Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A082276 Smallest number whose digits can be permuted to get exactly n distinct palindromes. 0

%I

%S 1,101,1001,10001,100001,112233,10000001,100122,10000111

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

%C Note that 10^n + 1 is always an upper bound.

%C 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. Adams-Watters_, Oct 26 2006

%e 101 gives two palindromes 101 and 011 = 11 hence a(2) = 101.

%e a(6) = 112233, The digit permutation gives six palindromes 123321,132231,213312,231132,312213,321123.

%Y Cf. A082274, A082275.

%K base,more,nonn

%O 1,2

%A _Amarnath Murthy_, Apr 13 2003

%E More terms from _Franklin T. Adams-Watters_, Oct 26 2006

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 2 07:40 EST 2020. Contains 338868 sequences. (Running on oeis4.)