1RB3LA4RB0RB2LA_1LB2LA3LA1RA1RZ

1RB3LA4RB0RB2LA_1LB2LA3LA1RA1RZ (bbch)

This is the current BB(2,5) champion. It halts with sigma score (and runtime) over $10^{10^{10^{3\,314\,360}}}$. It was discovered by Daniel Yuan and shared on Discord on 24 Jun 2024 and shared on the busy-beaver-discuss email list the next day.