A357096 Least number whose set of decimal digits coincides with the set of decimal digits of prime(n).

2, 3, 5, 7, 1, 13, 17, 19, 23, 29, 13, 37, 14, 34, 47, 35, 59, 16, 67, 17, 37, 79, 38, 89, 79, 10, 103, 107, 109, 13, 127, 13, 137, 139, 149, 15, 157, 136, 167, 137, 179, 18, 19, 139, 179, 19, 12, 23, 27, 29, 23, 239, 124, 125, 257, 236, 269, 127, 27, 128, 238, 239

Offset: 1

Author

Jean-Marc Rebert, Sep 12 2022

Keywords

• nonn
• base

Examples

			prime(5) = 11 and 1 have the same set of digits {1}, and 1 is the smallest such number, hence a(5) = 1.
		

Crossrefs

Cf. A179239, A179308.

Programs

Maple

f:= proc(p) local L,i;
  L:= sort(convert(convert(convert(p,base,10),set),list));
  if L[1] = 0 then L[1]:= L[2]; L[2]:= 0 fi;
  add(L[-i]*10^(i-1),i=1..nops(L)) end proc:
seq(f(ithprime(i)),i=1..100); # Robert Israel, Sep 12 2022

Mathematica

a[n_] := Module[{d = Union[IntegerDigits[Prime[n]]]}, If[d[[1]] == 0, d[[1;;2]] = d[[2;;1;;-1]]]; FromDigits[d]]; Array[a, 100] (* Amiram Eldar, Sep 13 2022 *)

PARI

a(n)=my(v=vecsort(digits(prime(n)),,8),w=v);if(v[1]==0,j=#v;w=if(j>2,v[3..j],[]);w=concat(Vecrev(v[1..2]),w));fromdigits(w)

Python

from sympy import prime
def a(n):
    s = "".join(sorted(set(str(prime(n)))))
    return int(s) if "0" not in s else int(s[1] + "0" + s[2:])
print([a(n) for n in range(1, 63)]) # Michael S. Branicky, Sep 12 2022