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 A114255 #16 Jul 28 2016 11:25:22 %S A114255 5,7,9,10,13,15,16,17,20,21,23,25,26,27,28,29,31,33,34,36,37,38,40,41, %T A114255 42,43,45,46,49,50,51,52,55,56,57,59,61,62,63,64,65,67,68,71,72,73,74, %U A114255 78,80,81,82,83,85,86,88,89,91,92,93,97,98,99,100,101,104,105,107,109 %N A114255 Numbers that are nontrivial (3 digits or more) palindromes when expressed in some base 2 or greater. %C A114255 All integers are trivially palindromes in base 1. All integers n>2 are trivially 2-digit palindromes because they can be represented as "11" in base n-1. %e A114255 5 is present because the palindrome (101 base 2) = 5; 803 is present because (30203 base 4) = 803. %t A114255 palindromeQ[n_, b_] := (id = IntegerDigits[n, b]) === Reverse[id] && Length[id] >= 3; palindromeQ[n_] := Or @@ (palindromeQ[n, #] & ) /@ Range[2, n-2]; Select[ Range[110], palindromeQ] (* _Jean-François Alcover_, Dec 16 2011 *) %o A114255 (Haskell) isPalindrome s = (s == reverse s) digits 0 _ = [] digits n b = n `rem` b : digits (n `quot` b) b check n = any isPalindrome $ takeWhile (\x -> length x > 2) $ map (digits n) [2..] main = mapM print $ filter check [1..] %o A114255 (PARI) isok(n) = for (b=2, n-1, if ((d=digits(n,b)) && (#d >= 3) && (Vecrev(d) == d), return (1));); \\ _Michel Marcus_, Jul 28 2016 %Y A114255 Cf. A060873-A060879, A060947-A060949, A123586. %K A114255 easy,base,nonn %O A114255 1,1 %A A114255 Jason Orendorff (jason.orendorff(AT)gmail.com), Feb 05 2006 %E A114255 Cross-references from _Charles R Greathouse IV_, Aug 04 2010