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 A057947 #2 Mar 30 2012 18:51:28 %S A057947 10,11,12,13,14,15,100,101,102,103,104,105,106,107,108,109,110,111, %T A057947 112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128, %U A057947 129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146 %N A057947 n has ambiguous representations in "bad hexadecimal": numbers with the digit 1 followed by a digit less than 6. %e A057947 a(5)=15 is on the list as this could be taken to represent 15*16^0=15 or 1*16^1+5*16^0=21 %Y A057947 Cf. A057946. %K A057947 base,easy,nonn %O A057947 0,1 %A A057947 _Henry Bottomley_, Oct 13 2000