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 A237454 #14 Dec 09 2014 03:33:09 %S A237454 1,11,3,13,113,1113,11113,111113,1111113,31,131,33,133,1133,11133, %T A237454 111133,1111133,11111133,111111133,1111111133,11111111133, %U A237454 111111111133,1111111111133,11111111111133,111111111111133,1111111111111133,11111111111111133,111111111111111133,311,1311,313,1313,11313,111313,1111313,11111313,331,1331,333,1333,11333 %N A237454 Minimal representation (considered minimal in any canonical base b > 3) of n in a binary system with two distinct digits "1" and "3", not allowing zeros, where a digit d in position p (p = 1,2,3,...,n) represents the value d^p. %C A237454 If digit "1" exists, the digits used in these numeral systems do not need to be consecutive. %e A237454 a(11) = 131 because 1^3 + 3^2 + 1^1 = 11. %Y A237454 Cf. A235860. %K A237454 nonn,base %O A237454 1,2 %A A237454 _Robin Garcia_, Feb 08 2014