OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
James Maynard and Brady Haran, Primes without a 7, Numberphile video (2019)
MATHEMATICA
Flatten[Table[Select[FromDigits/@Tuples[{2, 3}, n], PrimeQ], {n, 7}]] (* Harvey P. Dale, Jul 13 2012 *)
PROG
(PARI) go(n)=my(v=List([2]), x, t); for(d=1, n, x=10^d\9*2; forstep(i=1, 2^d-1, 2, if(ispseudoprime(t=x+fromdigits(binary(i))), listput(v, t)))); Vec(v) \\ Charles R Greathouse IV, Sep 14 2015
(Python)
from sympy import isprime
from itertools import count, islice, product
def agen(): # generator of terms
yield from [2, 3]
for d in count(2):
for first in product("23", repeat=d-1):
t = int("".join(first) + "3")
if isprime(t): yield t
print(list(islice(agen(), 34))) # Michael S. Branicky, Jun 08 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Jul 27 2008 at the suggestion of Dmitry Kamenetsky.
Edited by Charles R Greathouse IV, Mar 17 2010
STATUS
approved