A168586 Smallest n-digit prime with only digits 0 and 1, and having least digit sum (or 0, if no such prime exists).

0, 11, 101, 0, 10111, 101111, 1011001, 10010101, 101001001, 1000001011, 10000001101, 100000010101, 1000100000101, 10000000001011, 100000000100101, 1000000000100011, 10000000000001101, 100000000001010001, 1000000000000010011

Offset: 1

Author

Lekraj Beedassy, Nov 30 2009

Keywords

• nonn
• base

Links

• Robert Israel, Table of n, a(n) for n = 1..800

Crossrefs

Cf. A168587, A062339.

Programs

Maple

f:= proc(n) local s, c, i,Cands;
  for s from 2 to n do
    if s mod 3 = 0 then next fi;
    Cands:= sort(map(t -> 1 + 10^(n-1) + add(10^t[i],i=1..s-2), combinat:-choose([$1..n-2],s-2)));
    for c in Cands do if isprime(c) then return c fi od
  od;
  0
end proc:
map(f, [$1..20]); # Robert Israel, Aug 03 2020

Extensions

Extended by Ray Chandler, Dec 03 2009