A085414 Primes that are a concatenation of a prime and its first digit.

131, 191, 313, 373, 797, 1031, 1091, 1511, 1571, 1811, 1931, 3313, 3373, 3533, 3593, 3673, 3733, 3793, 3833, 7517, 7577, 7877, 9199, 9419, 9479, 9539, 9679, 9719, 9839, 10091, 10211, 10331, 10391, 10631, 10691, 11171, 12011, 12491, 12791, 12911

Offset

1,1

Comments

Also primes remaining prime after deleting last digit, but not all such primes. See also A012833, A024770, A033664, A069867.

Links

Table of n, a(n) for n=1..40.

Example

13 is a term because concatenation of 13 and 1 is prime.

Crossrefs

Cf. A085412, A085413, A012833, A024770, A033664, A069867.

Sequence in context: A180544 A032750 A270596 * A068686 A082807 A088288

Adjacent sequences: A085411 A085412 A085413 * A085415 A085416 A085417

Keyword

nonn,base

Author

Zak Seidov, Jun 29 2003

Status

approved