A091923 - OEIS

A091923

Primes whose decimal representations interpreted in base 11 are not prime.

11, 13, 17, 19, 23, 31, 37, 41, 47, 53, 59, 71, 73, 79, 83, 97, 101, 103, 107, 109, 113, 127, 131, 137, 149, 151, 157, 163, 167, 173, 179, 181, 191, 211, 223, 229, 233, 239, 241, 251, 257, 271, 277, 283, 293, 307, 311, 313, 317, 337, 347, 349, 359, 367, 383

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OFFSET

1,1

COMMENTS

A090862(A049084(a(n))) = 11.

LINKS

Marius A. Burtea, Table of n, a(n) for n = 1..1045

EXAMPLE

A000040(9)=23 in base 11 is 2*11^1 + 3*11^0 = 25 = 5^2, therefore 29 is a term.

MATHEMATICA

Select[Prime@Range@80, ! PrimeQ@FromDigits[IntegerDigits@#, 11] &] (* Vincenzo Librandi, Jul 01 2019 *)

PROG