A155089 - OEIS

A155089

Primes p such that the largest digit of the concatenation of p and the p-th prime is either 1 or 9.

17, 19, 29, 41, 43, 59, 79, 89, 97, 109, 127, 131, 139, 149, 157, 163, 167, 179, 191, 193, 197, 199, 211, 223, 229, 239, 251, 263, 269, 293, 317, 337, 349, 359, 373, 379, 389, 397, 401, 409, 419, 421, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499

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OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Prime[Range[250]], MemberQ[{1, 9}, Max[Join[IntegerDigits[ #], IntegerDigits[ Prime[#]]]]]&] (* Harvey P. Dale, Feb 08 2022 *)

PROG

(PARI) isok(p) = isprime(p) && (vecmax(digits(eval(concat(Str(p), Str(prime(p)))))) == 9); \\ Michel Marcus, Feb 18 2021

CROSSREFS

Cf. A000040.

Sequence in context: A132246 A038969 A065742 * A101396 A050266 A045803