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A154679
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Primes p such that the sum of digits of p+2 is a composite number.
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1
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2, 7, 11, 13, 17, 29, 31, 37, 43, 53, 61, 67, 71, 73, 79, 89, 97, 101, 103, 107, 127, 139, 151, 157, 163, 167, 179, 181, 193, 211, 223, 229, 233, 241, 251, 257, 269, 271, 277, 283, 293, 307, 313, 331, 337, 347, 349, 359, 367, 373, 379, 383, 397, 409, 421, 431
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OFFSET
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1,1
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COMMENTS
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LINKS
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MAPLE
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filter:= proc(n) local s;
if not isprime(n) then return false fi;
s:= convert(convert(n+2, base, 10), `+`);
s >= 4 and not isprime(s)
end proc:
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MATHEMATICA
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Select[Prime[Range[100]], CompositeQ[Total[IntegerDigits[#+2]]]&] (* Harvey P. Dale, Apr 28 2022 *)
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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