OFFSET
1,2
COMMENTS
Both even and odd k are counted. Variant of A134876.
PROG
(PARI) a(n) = sum(k=1, 2^n-1, ispseudoprime(k<<n+1))
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Jeppe Stig Nielsen, Jan 19 2020
STATUS
approved