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 A254319 #20 Feb 06 2015 05:51:30 %S A254319 27,108,125,128,129,135,138,143,159,160,184,187,189,196,207,209,216, %T A254319 219,243,249,256,259,265,276,295,297,329,341,351,375,403,429,451,458, %U A254319 469,497,512,529,621,625,671,679,729,781,795,837,841,892,896,908,916,932 %N A254319 Hyper economical numbers. %C A254319 The distinction between the economical numbers (A046759) is that the distinct digits are counted only instead all digits. Hence the definition: %C A254319 Write n as product of primes raised to powers, let D(n) = total number of distinct digits in product representation (number of distinct digits in all the primes and number of distinct digits in all the exponents that are greater than 1) and nbd(n) = A043537(n) number of distinct digits in n; sequence gives n such that D(n) < nbd(n). %e A254319 27 is in the sequence because 27 = 3 ^ 3 => D(27)= 1 < nbd(27)=2. %t A254319 Cases[Range[400], n_ /; Length[Union[Flatten[IntegerDigits[FactorInteger[n] /. 1 -> Sequence[]]]]]< Length[Union[Flatten[IntegerDigits[n]]]]] %o A254319 (PARI) for(n=1,10^3,s=[];F=factor(n);for(i=1,#F[,1],s=concat(s,digits(F[i,1]));if(F[i,2]>1,s=concat(s,digits(F[i,2]))));if(#vecsort(digits(n),,8)>#vecsort(s,,8),print1(n,", "))) \\ _Derek Orr_, Jan 30 2015 %Y A254319 Cf. A043537, A046760, A046758, A046759, A254318, A254321. %K A254319 nonn,base %O A254319 1,1 %A A254319 _Michel Lagneau_, Jan 28 2015