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 A158571 Primes whose digit sum is a single-digit 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 (list; graph; refs; listen; history; text; internal format)
 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 single-digit 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 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 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

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Last modified June 19 09:33 EDT 2021. Contains 345126 sequences. (Running on oeis4.)