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A179027
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Primes with a 3 as the only prime digit.
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2
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3, 13, 31, 43, 83, 103, 113, 131, 139, 163, 193, 311, 349, 389, 431, 439, 443, 463, 613, 631, 643, 683, 839, 863, 883, 983, 1013, 1031, 1039, 1063, 1093, 1103, 1163, 1193, 1301, 1319, 1361, 1381, 1399, 1439, 1483, 1493, 1613, 1663, 1693, 1831, 1913, 1931
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internal format)
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OFFSET
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1,1
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LINKS
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MAPLE
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filter:= proc(n) local L, t;
L:= convert(n, base, 10);
numboccur(3, L) = 1 and convert(L, set) intersect {2, 5, 7} = {}
end proc:
select(filter, [seq(ithprime(i), i=1..1000)]); # Robert Israel, Apr 21 2021
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PROG
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(Python)
from sympy import sieve
def ok(p): s=str(p); return set(s)&set("2357")=={'3'} and s.count('3')==1
def aupto(limit): return [p for p in sieve.primerange(1, limit+1) if ok(p)]
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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