OFFSET
1,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..20000 (first 1000 terms from Vincenzo Librandi)
James Maynard and Brady Haran, Primes without a 7, Numberphile video (2019)
MATHEMATICA
Flatten[Table[Select[FromDigits/@Tuples[{4, 9}, n], PrimeQ], {n, 8}]] (* Vincenzo Librandi, Jul 27 2012 *)
PROG
(PARI) is(N)=isprime(N)&&!#setminus(Set(digits(N)), [4, 9]) \\ M. F. Hasler, Sep 22 2020
CROSSREFS
KEYWORD
nonn,base
AUTHOR
STATUS
approved