cp's OEIS Frontend

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

%I A275450 #15 Aug 09 2016 14:32:11
%S A275450 3,9,21,27,34,35,36,37,38,39,41,42,43,44,45,46,50,51,52,53,56,57,58,
%T A275450 59,60,61,62,63,65,66,67,68,69,70,73,74,75,76,77,79,81,82,83,84,85,86,
%U A275450 87,88,89,90,91,92,93,94,95,96,97,98,99,103,107
%N A275450 Numbers n such that primorial(n) contains n as a string of digits.
%H A275450 Robert Israel, <a href="/A275450/b275450.txt">Table of n, a(n) for n = 1..10000</a>
%F A275450 A275451(a(n)) > 0.
%e A275450 Primorial(3) equals 30, which contains 3, therefore 3 is in the sequence.
%p A275450 count:= 0:
%p A275450 P:= 2; p:= 2;
%p A275450 for n from 2 while count < 1000 do
%p A275450   p:= nextprime(p);
%p A275450   P:= P*p;
%p A275450   if StringTools:-Search(sprintf("%d",n),sprintf("%d",P))<>0 then
%p A275450      count:= count+1;
%p A275450      A[count]:= n;
%p A275450   fi
%p A275450 od:
%p A275450 seq(A[i],i=1..count); # _Robert Israel_, Jul 29 2016
%t A275450 primorial[n_]:=Product[Prime[i],{i,1,n}];
%t A275450 Select[Range@500,StringContainsQ[ToString[primorial[#]],ToString[#]]&]
%o A275450 (Perl) use ntheory ":all"; my @a275450 = grep { index(pn_primorial($_),$_) >= 0 } 1 .. 1000; say "@a275450"; # _Dana Jacobsen_, Aug 09 2016
%Y A275450 Cf. A002110 (primorial numbers), A275451.
%K A275450 base,easy,nonn
%O A275450 1,1
%A A275450 _Ivan N. Ianakiev_, Jul 28 2016