let k be Nat; :: thesis: for p being Prime st p * p <= k & k < 121 & not p = 2 & not p = 3 & not p = 5 holds
p = 7
let p be Prime; :: thesis: ( p * p <= k & k < 121 & not p = 2 & not p = 3 & not p = 5 implies p = 7 )
assume ( p * p <= k & k < 121 ) ; :: thesis: ( p = 2 or p = 3 or p = 5 or p = 7 )
then p * p < 11 * 11 by XXREAL_0:2;
hence ( p = 2 or p = 3 or p = 5 or p = 7 ) by Th7, NAT_4:1; :: thesis: verum