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.

A050695 Composite numbers k such that none of the prime factors of k is a substring of k.

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%I A050695 #25 Aug 04 2021 02:22:06
%S A050695 4,6,8,9,10,14,16,18,21,27,34,38,40,44,46,48,49,51,54,56,57,58,60,64,
%T A050695 66,68,69,74,76,78,80,81,84,86,87,88,90,91,94,96,98,99,100,104,106,
%U A050695 108,111,114,116,117,118,119,121,129,133,134,136,140,141,143,144,146
%N A050695 Composite numbers k such that none of the prime factors of k is a substring of k.
%C A050695 A131929(a(n)) = 0; together with 1, complement of A131930. - _Reinhard Zumkeller_, Jul 30 2007
%H A050695 Reinhard Zumkeller, <a href="/A050695/b050695.txt">Table of n, a(n) for n = 1..10000</a>
%e A050695 114 = 2*3*19.
%t A050695 d[n_]:=IntegerDigits[n]; t={}; Do[le1=Max@@Length/@(t1=d[First/@FactorInteger[n]]); t2=Flatten[Table[Partition[d[n],i,1],{i,le1}],1]; If[!PrimeQ[n]&&Intersection[t1,t2]=={},AppendTo[t,n]],{n,2,146}]; t (* _Jayanta Basu_, May 31 2013 *)
%t A050695 npfsQ[n_]:=Module[{idn=IntegerDigits[n],f=FactorInteger[n][[All,1]]}, And@@ Table[SequenceCount[idn,IntegerDigits[f[[i]]]]==0,{i, Length[ f]}]]; Select[Range[200],CompositeQ[#] && npfsQ[#]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 28 2016 *)
%Y A050695 Cf. A050694, A050696, A035139, A050698.
%K A050695 nonn,base,nice
%O A050695 1,1
%A A050695 _Patrick De Geest_, Aug 15 1999