theorem :: NUMBER02:36

for n being Nat holds
( not 8 divides n iff ex k being Nat st
( n = (8 * k) + 1 or n = (8 * k) + 2 or n = (8 * k) + 3 or n = (8 * k) + 4 or n = (8 * k) + 5 or n = (8 * k) + 6 or n = (8 * k) + 7 ) )