A158571 Primes whose digit sum is a single-digit nonprime.

13, 17, 31, 53, 71, 103, 107, 211, 233, 251, 431, 503, 521, 701, 1021, 1061, 1151, 1201, 1223, 1511, 1601, 2011, 2141, 2213, 2411, 3001, 3023, 3041, 3203, 3221, 4013, 4211, 5003, 5021, 6011, 6101, 7001, 10007, 10061, 10111, 10133, 10151, 10223, 10313

Offset: 1

Author

Parthasarathy Nambi, Mar 21 2009

Keywords

• base
• nonn

Comments

It is interesting to observe that it is hard to find (I found none) primes whose digit sum is 6. On the contrary, it is easier to find primes whose digit sum is 8.

The digit sum 6 does not occur here because a number with digit sum 6 is divisible by 3 and therefore not prime. - R. J. Mathar, Mar 26 2009

Examples

			1061 is a prime whose digit sum is 8, which is a single-digit nonprime.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000
• Chris Caldwell, The First 1,000 Primes

Crossrefs

Cf. A158217.

Programs

Maple

for i from 1 to 8 do if member(i,[1,3,7]) then S[1,i]:= {i} else S[1,i]:= {} fi od:
for d from 2 to 5 do
  for x from 1 to 8 do
    S[d,x]:= {};
    for y from 0 to x-1 do
      S[d,x]:= S[d,x] union map(t -> 10^(d-1)*y + t, S[d-1,x-y])
od od od:
select(isprime, S[5,4] union S[5,8]); # Robert Israel, Apr 14 2021

Formula

Union of A062339 and A062343. - R. J. Mathar, Mar 26 2009

Extensions

Extended by R. J. Mathar, Mar 26 2009