cp's OEIS Frontend

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.

A025283 Composites that use the same digits as their prime factorization.

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%I A025283 #17 Jun 29 2017 00:02:12
%S A025283 25,121,1255,2349,5120,12337,12955,17482,25105,41323,43375,93217,
%T A025283 100255,101299,105295,107329,117067,124483,127417,129595,132565,
%U A025283 145273,146137,149782,163797,174082,174298,174793,174982,191239,250105,256315,263155
%N A025283 Composites that use the same digits as their prime factorization.
%C A025283 Here exponents equal to 1 are not taken into account, so 1255 = 5^1*251^1 = 5*251 is a term. Prime numbers are excluded because they all trivially use the same digits as their prime factorization. If, on the contrary, exponents equal to 1 are counted, the resulting sequence is A075047. - _Giovanni Resta_, Jul 14 2015
%C A025283 An interesting example of the factorization digits appearing in the same order as in its composite generator: 13532385396179 = 13 * 53^2 * 3853 * 96179. - _Hans Havermann_, Jun 28 2017
%H A025283 Giovanni Resta, <a href="/A025283/b025283.txt">Table of n, a(n) for n = 1..10000</a>
%t A025283 Select[Range[10^5], !PrimeQ@ # && Sort@ IntegerDigits@ # == Sort@ Flatten@ IntegerDigits@ Select[ Flatten@ FactorInteger@ #, #>1 &] &] (* _Giovanni Resta_, Jul 14 2015 *)
%Y A025283 Cf. A075047, A260046, A260047, A260048, A260049, A260050, A260051, A260052, A260053, A260054, A260055.
%K A025283 base,nonn
%O A025283 1,1
%A A025283 _David W. Wilson_