

A171740


The first number palindromic with n digits in more than one base (shown in base 10).


22



1, 8, 26, 624, 2293, 207702, 186621, 342324801, 27924649, 260311602096, 1556085529, 248876637484140, 318713056300, 2544221971606336, 4712469842177, 530386561769238496, 1939137135947326
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OFFSET

1,2


COMMENTS

This sequence gives the first value (represented in base 10) that is palindromic  i.e., the same when its digits are reflected about the center  with n >= 1 digits in two different bases.
Currently waiting on doubly 18palindrome. The 19palindrome is one in bases 10 and 11, 6411682614162861146 in base 10. For some time I was laboring under the impression that the new terms now added  starting at 9palindromes  were too difficult to find, thinking a change I recently made would not increase programming efficiency as much as it did. The results come from the research done for the sequences labeled with A216*** shown below. The other crossreferenced sequences, A171***, deal with higher orders of multiplicity and such things.  James G. Merickel, Sep 19 2012


LINKS

Table of n, a(n) for n=1..17.


EXAMPLE

a(2)=8 is 11 in base 7 and 22 in base 3.
a(3)=26 is 101 in base 5 and 222 in base 3.
a(4)=624 is 1551 in base 7 and 4444 in base 5.
a(7)=186621 is 3555553 in base 6 and 1405041 in base 7.
a(8)=342324801 is 96788769 in base 12 and 14677641 in base 16.


CROSSREFS

Cf. A171701, A171702, A171703, A171704, A171705, A171706, A171741, A171742, A216840, A216841, A216843, A216899, A216900, A216901, A216902, A216903, A216904, A216905, A216906, A216907, A216908, A216909, A216910.
Sequence in context: A240291 A203635 A000810 * A129663 A112646 A119522
Adjacent sequences: A171737 A171738 A171739 * A171741 A171742 A171743


KEYWORD

more,nonn,base


AUTHOR

James G. Merickel, Dec 17 2009


EXTENSIONS

Corrected typo in example by Chai Wah Wu, Jul 18 2015


STATUS

approved



