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.

A249125 Composite numbers which are a multiple of the concatenation of their prime factors A084317.

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%I A249125 #8 May 29 2017 08:47:39
%S A249125 4,8,9,16,25,27,32,49,50,64,81,100,121,125,128,169,200,243,250,256,
%T A249125 289,343,361,400,500,512,529,625,729,800,841,961,1000,1024,1250,1331,
%U A249125 1369,1600,1681,1849,2000,2048,2187,2197,2209,2401,2500,2809,3125,3200,3481,3721,4000,4096,4489,4913,5000,5041,5329,6241,6250,6400
%N A249125 Composite numbers which are a multiple of the concatenation of their prime factors A084317.
%C A249125 Prime numbers are excluded since they trivially satisfy the condition.
%C A249125 Multiplicity of the prime factors is ignored.
%C A249125 Among the first 10000 terms, the 182 which are not prime powers are of the form 2^h * 5^k. - _Giovanni Resta_, May 29 2017
%H A249125 Giovanni Resta, <a href="/A249125/b249125.txt">Table of n, a(n) for n = 1..10000</a>
%t A249125 Select[Range[6400], CompositeQ[#] &&  Mod[#, FromDigits@ Flatten[ IntegerDigits /@ First /@ FactorInteger@#]] == 0 &] (* _Giovanni Resta_, May 29 2017 *)
%o A249125 (PARI) for(n=2,9999,isprime(n)||n%A084317(n)||print1(n","))
%Y A249125 Cf. A084317, A069872, A224930, A240265.
%K A249125 nonn,base
%O A249125 1,1
%A A249125 _M. F. Hasler_, Oct 21 2014