

A306084


Primes which remain prime after all even digits are removed.


2



3, 5, 7, 11, 13, 17, 19, 23, 31, 37, 43, 47, 53, 59, 67, 71, 73, 79, 83, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 263, 271, 283, 307, 311, 313, 317, 331, 337, 347, 353, 359, 367, 373, 379, 397, 419, 431, 443, 463, 467, 479, 487, 503, 509, 523
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OFFSET

1,1


COMMENTS

Obviously all primes with just odd digits are members of this sequence.


LINKS

Table of n, a(n) for n=1..70.


EXAMPLE

23 is a member because if the digit 2 is removed the resulting number becomes 3 which is a prime.


MATHEMATICA

Select[Prime@ Range@ 100, PrimeQ[ FromDigits[ Select[ IntegerDigits@#, OddQ]]] &]


PROG

(PARI) isok(p) = isprime(p) && isprime(fromdigits(select(x>(x % 2), digits(p)))); \\ Michel Marcus, Jun 21 2018


CROSSREFS

Cf. A030096 (subsequence), A306085, A306086.
Sequence in context: A278454 A064534 A139758 * A060770 A246568 A120334
Adjacent sequences: A306081 A306082 A306083 * A306085 A306086 A306087


KEYWORD

nonn,base


AUTHOR

Zak Seidov and Robert G. Wilson v, Jun 20 2018


STATUS

approved



