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A156756
Primes not containing exactly two odd digits.
5
2, 3, 5, 7, 23, 29, 41, 43, 47, 61, 67, 83, 89, 113, 131, 137, 139, 151, 157, 173, 179, 191, 193, 197, 199, 223, 227, 229, 241, 263, 269, 281, 283, 311, 313, 317, 331, 337, 353, 359, 373, 379, 397, 401, 409, 421, 443, 449, 461, 463, 467, 487, 557, 571, 577, 593
OFFSET
1,1
COMMENTS
Odd digits are 1, 3, 5, 7 or 9.
LINKS
FORMULA
a(n) ~ n log n. On the Riemann hypothesis, a(n) = ali(n) + O(n^k log n) where ali is the inverse logarithmic integral and k = log 5/log 10 = 0.69897.... - Charles R Greathouse IV, Apr 08 2016
MATHEMATICA
checkQ[n_] := Module[{d = IntegerDigits[n]}, Length[Select[d, OddQ]] != 2]; Select[Prime[Range[200]], checkQ] (* T. D. Noe, Jun 06 2012 *)
PROG
(PARI) is(n)=#select(d->d%2, digits(n))!=2 && isprime(n) \\ Charles R Greathouse IV, Apr 08 2016
CROSSREFS
Cf. A000040.
Sequence in context: A343590 A343591 A323578 * A225659 A068690 A069556
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
183 replaced by 283 - R. J. Mathar, Feb 20 2009
Definition clarified by Jonathan Sondow, Jun 06 2012
STATUS
approved