OFFSET
0,2
COMMENTS
Thue's proof, that there exist infinitely many primes, shows also that n+1 is a lower bound for a(n) (see Ribenboim, 2004).
REFERENCES
Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See pp. 9-10.
LINKS
MATHEMATICA
a[n_]:=PrimePi[4^(n^2)]; Array[a, 6, 0]
PROG
(Python)
from sympy import primepi
def A382481(n): return primepi(1<<(n**2<<1)) # Chai Wah Wu, Mar 29 2025
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Stefano Spezia, Mar 28 2025
STATUS
approved
