let k be Nat; for p being Prime st p * p <= k & k < 361 & not p = 2 & not p = 3 & not p = 5 & not p = 7 & not p = 11 & not p = 13 holds
p = 17
let p be Prime; ( p * p <= k & k < 361 & not p = 2 & not p = 3 & not p = 5 & not p = 7 & not p = 11 & not p = 13 implies p = 17 )
assume
( p * p <= k & k < 361 )
; ( p = 2 or p = 3 or p = 5 or p = 7 or p = 11 or p = 13 or p = 17 )
then
p * p < 19 * 19
by XXREAL_0:2;
hence
( p = 2 or p = 3 or p = 5 or p = 7 or p = 11 or p = 13 or p = 17 )
by Th13, NAT_4:1; verum