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A275450 Numbers n such that primorial(n) contains n as a string of digits. 2

%I

%S 3,9,21,27,34,35,36,37,38,39,41,42,43,44,45,46,50,51,52,53,56,57,58,

%T 59,60,61,62,63,65,66,67,68,69,70,73,74,75,76,77,79,81,82,83,84,85,86,

%U 87,88,89,90,91,92,93,94,95,96,97,98,99,103,107

%N Numbers n such that primorial(n) contains n as a string of digits.

%H Robert Israel, <a href="/A275450/b275450.txt">Table of n, a(n) for n = 1..10000</a>

%F A275451(a(n)) > 0.

%e Primorial(3) equals 30, which contains 3, therefore 3 is in the sequence.

%p count:= 0:

%p P:= 2; p:= 2;

%p for n from 2 while count < 1000 do

%p p:= nextprime(p);

%p P:= P*p;

%p if StringTools:-Search(sprintf("%d",n),sprintf("%d",P))<>0 then

%p count:= count+1;

%p A[count]:= n;

%p fi

%p od:

%p seq(A[i],i=1..count); # _Robert Israel_, Jul 29 2016

%t primorial[n_]:=Product[Prime[i],{i,1,n}];

%t Select[Range@500,StringContainsQ[ToString[primorial[#]],ToString[#]]&]

%o (Perl) use ntheory ":all"; my @a275450 = grep { index(pn_primorial($_),$_) >= 0 } 1 .. 1000; say "@a275450"; # _Dana Jacobsen_, Aug 09 2016

%Y Cf. A002110 (primorial numbers), A275451.

%K base,easy,nonn

%O 1,1

%A _Ivan N. Ianakiev_, Jul 28 2016

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Last modified April 20 16:17 EDT 2019. Contains 322310 sequences. (Running on oeis4.)