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A154679
Primes p such that the sum of digits of p+2 is a composite number.
1
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
OFFSET
1,1
COMMENTS
Primes p such that p+2 is in A104211. [R. J. Mathar, Jan 15 2009]
LINKS
MAPLE
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:
select(filter, [$2..1000]); # Robert Israel, Mar 13 2019
MATHEMATICA
Select[Prime[Range[100]], CompositeQ[Total[IntegerDigits[#+2]]]&] (* Harvey P. Dale, Apr 28 2022 *)
CROSSREFS
Sequence in context: A175442 A020597 A140563 * A191052 A338173 A138889
KEYWORD
base,easy,nonn
AUTHOR
Giovanni Teofilatto, Jan 14 2009
EXTENSIONS
Extended by R. J. Mathar, Jan 15 2009
STATUS
approved