A168588 Smallest p(n)-digit prime with digit sum n, and made up of digits 0 and 1 only, where p(n)=A000040(n) (or 0, if no such prime exists).

0, 101, 0, 1011001, 10000110011, 0, 10000000010101111, 1000000000001111111, 0, 10000000000000000101101111101, 1000000000000000000011111110111, 0, 10000000000000000000000000011111111110101, 1000000000000000000000000000110111111011111

Offset

1,2

Comments

a(3n) = 0.

Links

Robert Israel, Table of n, a(n) for n = 1..168

Maple

g:= proc(L) local i, m;
  m:= -1;
  for i from 1 do
     if L[i] = 1 then
       if m = -1 then m:= i fi;
       if L[i+1] = 0 then
         return [1$(i-m), 0$(m-1), 0, 1, op(L[i+2..-1])]
       fi
     fi
  od
end proc:
f:= proc(n) local L, x, pn, i;
  if n mod 3 = 0 then return 0 fi;
  pn:= ithprime(n);
  L:= [1$(n-1), 0$(pn-n), 1];
  do
    x:= add(L[i]*10^(i-1), i=1..pn);
    if isprime(x) then return x fi;
    L:= g(L);
  od
end proc:
map(f, [$1..16]); # Robert Israel, Feb 01 2021

Crossrefs

Cf. A036929

Sequence in context: A279546 A279699 A279602 * A266323 A280372 A181721

Adjacent sequences: A168585 A168586 A168587 * A168589 A168590 A168591

Keyword

nonn,base

Author

Lekraj Beedassy, Nov 30 2009

Extensions

Extended by Ray Chandler, Dec 03 2009

Status

approved