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A238647 Primes which are not the concatenation of two primes. 1
2, 3, 5, 7, 11, 13, 17, 19, 29, 31, 41, 43, 47, 59, 61, 67, 71, 79, 83, 89, 97, 101, 103, 107, 109, 127, 131, 139, 149, 151, 157, 163, 167, 179, 181, 191, 199, 227, 239, 251, 257, 263, 269, 277, 281, 307, 349, 401, 409, 419, 421, 431, 439, 443, 449, 457, 461 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

223 is the first term in A141409 which is not in this sequence.

In this sequence, a prime preceded by one or more zeros is not considered to be a prime.

LINKS

Table of n, a(n) for n=1..57.

EXAMPLE

59 is in the sequence because 5 is prime but 9 is not prime.

223 is not in the sequence because both 2 and 23 are primes.

CROSSREFS

Cf. A141409, A105184 (complement), A238056, A238057, A238499.

Sequence in context: A133956 A176164 A141409 * A348358 A171821 A004051

Adjacent sequences:  A238644 A238645 A238646 * A238648 A238649 A238650

KEYWORD

nonn,base

AUTHOR

Colin Barker, Mar 02 2014

STATUS

approved

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Last modified January 21 03:47 EST 2022. Contains 350473 sequences. (Running on oeis4.)