cp's OEIS Frontend

A235693 Semiprimes which have one or more occurrences of exactly five different digits.

%I A235693 #18 Jul 06 2018 23:15:34
%S A235693 10237,10238,10239,10249,10265,10279,10294,10297,10327,10342,10345,
%T A235693 10347,10349,10358,10367,10378,10379,10389,10394,10397,10423,10435,
%U A235693 10462,10473,10483,10489,10493,10495,10497,10523,10537,10543,10546,10547,10562,10573,10579
%N A235693 Semiprimes which have one or more occurrences of exactly five different digits.
%C A235693 The first term having a repeated digit is 100235.
%C A235693 The first term that is a square is 12769. - _Robert Israel_, Jul 06 2018
%H A235693 Robert Israel, <a href="/A235693/b235693.txt">Table of n, a(n) for n = 1..6240</a>
%p A235693 # to get all terms with 5 digits S:= combinat:-choose([$0..9],5):
%p A235693 f:= proc(x) local s,L;
%p A235693       L:= convert(x,base,5);      if nops(L) < 5 then L:= [op(L),0$(5-nops(L))] fi;      if nops(convert(L,set))<5 then return NULL fi;
%p A235693       op(select(t -> t > 10^4 and numtheory:-bigomega(t)=2, map(s -> add(s[L[i]+1]*10^(i-1),i=1..5),S)))
%p A235693 end proc:
%p A235693 sort(map(f, [$1..5^5-1])); # _Robert Israel_, Jul 06 2018
%t A235693 Select[Range[10000,11000],PrimeOmega[#]==2&&Count[DigitCount[#],0]==5&] (* _Harvey P. Dale_, Apr 08 2015 *)
%o A235693 (PARI)
%o A235693 list(lim)=my(v=List(), t); forprime(p=2, sqrt(lim), t=p; forprime(q=p, lim\t, listput(v, t*q))); vecsort(Vec(v)) \\ From A001358
%o A235693 b=list(15000); s=[]; for(n=1, #b, if(#vecsort(eval(Vec(Str(b[n]))),,8)==5, s=concat(s, b[n]))); s
%Y A235693 Cf. A235690-A235692, A235694-A235696.
%Y A235693 Cf. A235154-A235161.
%K A235693 nonn,base
%O A235693 1,1
%A A235693 _Colin Barker_, Jan 14 2014