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A371352
Prime numbers such that the sum of their prime digits is equal to the sum of their nonprime digits.
2
167, 211, 541, 617, 761, 853, 1021, 1201, 1423, 1559, 1607, 1973, 2011, 2143, 2341, 2383, 2833, 3467, 3719, 3823, 3917, 4051, 4231, 4637, 4673, 5261, 5443, 5519, 5591, 6473, 6521, 6701, 7193, 7643, 7687, 7867, 8053, 8233, 8677, 9137, 9173, 9371, 9551
OFFSET
1,1
LINKS
EXAMPLE
9173 is a term because it is a prime number whose prime digits and nonprime digits have the same sum: 3 + 7 = 1 + 9 = 10.
MATHEMATICA
Select[Prime[Range[1200]], Plus @@ Select[d = IntegerDigits[#], PrimeQ[#1] &] == Plus @@ Select[d, ! PrimeQ[#1] &] &] (* Amiram Eldar, Mar 22 2024 *)
PROG
(Python)
from sympy import isprime
def ok(n):
if not isprime(n): return False
s, sums = str(n), [0, 0]
for c in s: sums[int(c in "2357")] += int(c)
return sums[0] == sums[1]
print([k for k in range(10**4) if ok(k)]) # Michael S. Branicky, Apr 23 2024
CROSSREFS
Cf. A000040, A156343 (equal number of prime and nonprime digits).
Sequence in context: A273549 A299379 A097400 * A142664 A247941 A338343
KEYWORD
nonn,base
AUTHOR
Gonzalo Martínez, Mar 19 2024
STATUS
approved