A306084 Primes which remain prime after all even digits are removed.

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

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 A338132

Adjacent sequences: A306081 A306082 A306083 * A306085 A306086 A306087

Keyword

nonn,base

Author

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

Status

approved