A057880 Primes with 4 distinct digits that remain prime (no leading zeros allowed) after deleting all occurrences of its digits d.
6173, 12239, 16673, 19531, 19973, 21613, 22397, 22937, 34613, 36137, 47933, 51193, 54493, 56519, 56531, 56591, 69491, 69497, 72937, 76873, 93497, 96419, 96479, 96497, 98837, 112939, 118213, 131779, 143419, 144497, 159319, 163337
Offset: 1
Links
- Robert Israel, Table of n, a(n) for n = 1..653
Programs
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Maple
filter:= proc(L) local d,Lp,i; if L[-1]=0 then return false fi; if not isprime(add(L[i]*10^(i-1),i=1..nops(L))) then return false fi; for d in convert(L,set) do Lp:= remove(`=`,L,d); if Lp[-1] = 0 or not isprime(add(Lp[i]*10^(i-1),i=1..nops(Lp))) then return false fi; od; true end proc: getCands:= proc(n, m) option remember; if m = 1 then return [seq([d$n], d=0..9)] fi; if n < m then return [] fi; [seq(seq([i,op(L)],i= {$0..9} minus convert(L,set)),L = procname(n-1,m-1)), seq(seq([i,op(L)],i=convert(L,set)),L = procname(n-1,m))] end proc: [seq(op(sort(map(t->add(t[i]*10^(i-1),i=1..nops(t)),select(filter,getCands(d,4))))),d=4..6)]; # Robert Israel, Jan 19 2017
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Mathematica
p4dQ[n_]:=Module[{idn=IntegerDigits[n]},Count[idn,0]==0 && Count[ DigitCount[ n],0]==6&&AllTrue[FromDigits/@Table[DeleteCases[idn,k],{k,Union[idn]}],PrimeQ]]; Select[Prime[Range[ 15000]],p4dQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 30 2017 *)
Extensions
Offset changed by Robert Israel, Jan 19 2017