Hello,
prime_pi(281474961965055) gives correct output 8731188419994.
prime_pi(281474961965056) gives wrong result 8731188419993.
Please note that second input is greater than first, however it produces smaller number of primes. The second output is obviously wrong.
It was tested on CoCalc.com free trial and the bug is easily reproducible.
Should I open the ticket? Is it a known error?
Thanks
Martin Zeman