

A158571


Primes whose digit sum is a singledigit nonprime.


1



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
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OFFSET

1,1


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


LINKS

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


FORMULA

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


EXAMPLE

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


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 x1 do
S[d, x]:= S[d, x] union map(t > 10^(d1)*y + t, S[d1, xy])
od od od:
select(isprime, S[5, 4] union S[5, 8]); # Robert Israel, Apr 14 2021


CROSSREFS

Cf. A158217.
Sequence in context: A116671 A062338 A143863 * A176882 A272403 A159614
Adjacent sequences: A158568 A158569 A158570 * A158572 A158573 A158574


KEYWORD

base,nonn


AUTHOR

Parthasarathy Nambi, Mar 21 2009


EXTENSIONS

Extended by R. J. Mathar, Mar 26 2009


STATUS

approved



