This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A216841 #23 Aug 22 2015 00:49:04 %S A216841 24,18,8,10,12,14,16,18,15,22,18,26,21,30,24,34,24,38,30,28,33,46,32, %T A216841 50,39,36,35,58,40,62,40,44,51,70,45,74,57,52,48,82,56,86,55,54,69,94, %U A216841 60,98,60,68,65,106,63,66,70,76,87,118,70,122,93,84,80,78,77 %N A216841 Smallest palindromic number of length 2 in two bases differing by n. %C A216841 This and other sequences in this collection -- that runs through 17-digit palindromes but (for now) excludes 16-digit ones (but see A216910) -- have offset 2 because an even-length palindrome in one base ends in 0 in the base one larger. After its first two terms, this particular sequence in the collection is trivial. The collection in its entirety are the A216*** cross-references plus this one. The smaller of the pair of bases here are (in sequence) 5, 5, 3, 4, 5, 6, 7, 8, 9. Aside from the first two sequences being switched in order of their A-numbers, the others are in order (but note that only the last 12 are without gaps in the A-sequencing). The A171*** cross-references are to a variety of record small multi-base palindromes. %H A216841 Chai Wah Wu, <a href="/A216841/b216841.txt">Table of n, a(n) for n = 2..10000</a> %e A216841 All numbers smaller than 24 (in base 10) fail to have two bases differing by 2 in which the number is a 2-digit palindrome. Decimal number 24 is 44 in base 5 and is 33 in base 7. Similarly, for the second term here, the facts that decimal number 18 is 33 in base 5 and 22 in base 8 and that no smaller number than decimal 18 has 2 bases in which it is a 2-digit palindrome result in its position here. %e A216841 a(10) = 15 is 33 in base 4 and 11 in base 14. - _Chai Wah Wu_, Aug 19 2015 %Y A216841 Cf. A171701, A171702, A171703, A171704, A171705, A171706, A171740, A171741, A171742, A171775, A216840, A216843, A216899, A216900, A216901, A216902, A216903, A216904, A216905, A216906, A216907, A216908, A216909, A216910. %K A216841 nonn,base %O A216841 2,1 %A A216841 _James G. Merickel_, Sep 19 2012 %E A216841 More terms and corrected a(10) from _Chai Wah Wu_, Aug 19 2015