cp's OEIS Frontend

A216840 Smallest palindromic number of 3 digits in two bases differing by n.

%I A216840 #24 Aug 22 2015 00:48:55
%S A216840 46,26,121,109,157,211,209,197,257,307,381,576,463,676,601,701,757,
%T A216840 842,929,1086,1123,1445,1333,1717,1297,1801,1522,2092,1765,2393,2026,
%U A216840 2026,2305,2696,2501,2701,2757,2971,3133,3600,3421,3718,4411,3845,4551,4031,4691
%N A216840 Smallest palindromic number of 3 digits in two bases differing by n.
%C A216840 This is one of a collection of sequences of doubly palindromic numbers of same lengths in each of two bases.  The lengths go from 2 through 17, excluding 16 (only one term available at present), and the order of the first two of these are switched in terms of their A-numbers.  These are the A216*** cross-references.  The 171*** c-refs are to a variety of record multiple-base palindromes.  Larger comments are to be found -- will generally be -- in the 2-palindrome sequence.  The smaller bases of a pair here are (in sequence) 4, 3, 6, 5, 6, 7, 6, 6, 7, 7.
%H A216840 Chai Wah Wu, <a href="/A216840/b216840.txt">Table of n, a(n) for n = 1..10000</a>
%e A216840 The first entry here, 46 in base 10, is represented as 222 in base 4 and 141 in base 5. The 2nd entry here, 26 in base 10, is represented as 222 in base 3 and 101 in base 5. The next is then the smallest in bases that differ by 3, bases 6 and 9 by what is in the comment.
%e A216840 a(3) = 121 is 232 in base 7, a(5) = 157 is 313 in base 7 and 111 in base 12, a(6) = 211 is 323 in base 8 and 111 in base 14. - _Chai Wah Wu_, Aug 19 2015
%Y A216840 Cf. A171701, A171702, A171703, A171704, A171705, A171706, A171740, A171741, A171742, A171775, A216841, A216843, A216899, A216900, A216901, A216902, A216903, A216904, A216905, A216906, A216907, A216908, A216909, A216910.
%K A216840 nonn,base
%O A216840 1,1
%A A216840 _James G. Merickel_, Sep 19 2012
%E A216840 More terms and corrected a(3), a(5) and a(6) by _Chai Wah Wu_, Aug 19 2015