cp's OEIS Frontend

A171740 The first number palindromic with n digits in more than one base (shown in base 10).

%I A171740 #24 Jul 19 2015 09:08:56
%S A171740 1,8,26,624,2293,207702,186621,342324801,27924649,260311602096,
%T A171740 1556085529,248876637484140,318713056300,2544221971606336,
%U A171740 4712469842177,530386561769238496,1939137135947326
%N A171740 The first number palindromic with n digits in more than one base (shown in base 10).
%C A171740 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.
%C A171740 Currently waiting on doubly 18-palindrome.  The 19-palindrome 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 9-palindromes -- 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 cross-referenced sequences, A171***, deal with higher orders of multiplicity and such things. - _James G. Merickel_, Sep 19 2012
%e A171740 a(2)=8 is 11 in base 7 and 22 in base 3.
%e A171740 a(3)=26 is 101 in base 5 and 222 in base 3.
%e A171740 a(4)=624 is 1551 in base 7 and 4444 in base 5.
%e A171740 a(7)=186621 is 3555553 in base 6 and 1405041 in base 7.
%e A171740 a(8)=342324801 is 96788769 in base 12 and 14677641 in base 16.
%Y A171740 Cf. A171701, A171702, A171703, A171704, A171705, A171706, A171741, A171742, A216840, A216841, A216843, A216899, A216900, A216901, A216902, A216903, A216904, A216905, A216906, A216907, A216908, A216909, A216910.
%K A171740 more,nonn,base
%O A171740 1,2
%A A171740 _James G. Merickel_, Dec 17 2009
%E A171740 Corrected typo in example by _Chai Wah Wu_, Jul 18 2015