Oganesson is produced by collision of   $\underset{98}{\overset{249}{\mathrm{Cf}}}$  atoms and

Oganesson is a synthetic chemical element with the symbol Og and atomic number 118.

It is produced by collisions of californium-249 atoms and calcium-48 ions.

${\mathrm{Cf}}_{98}^{249}+{\mathrm{Ca}}_{20}^{48}\to {\mathrm{Og}}_{118}^{294}+3 {\mathrm{n}}_0^1$