let n be Nat; ( n > 1 implies (1 / 5) * ((2 |^ ((4 * n) + 2)) + 1) is composite )
assume A1:
n > 1
; (1 / 5) * ((2 |^ ((4 * n) + 2)) + 1) is composite
set W = (2 |^ ((4 * n) + 2)) + 1;
set L = ((2 |^ ((2 * n) + 1)) - (2 |^ (n + 1))) + 1;
set R = ((2 |^ ((2 * n) + 1)) + (2 |^ (n + 1))) + 1;
A2:
(2 |^ ((2 * n) + 1)) * (2 |^ ((2 * n) + 1)) = 2 |^ (((2 * n) + 1) + ((2 * n) + 1))
by NEWTON:8;
A3:
2 * (2 |^ ((2 * n) + 1)) = 2 |^ (((2 * n) + 1) + 1)
by NEWTON:6;
A4:
(2 |^ (n + 1)) * (2 |^ (n + 1)) = 2 |^ ((n + 1) + (n + 1))
by NEWTON:8;
2 |^ (((2 * n) + 1) + 1) = 2 |^ ((n + 1) + (n + 1))
;
then A5:
2 |^ ((4 * n) + 2) = (((2 |^ ((2 * n) + 1)) * (2 |^ ((2 * n) + 1))) + (2 * (2 |^ ((2 * n) + 1)))) - ((2 |^ (n + 1)) * (2 |^ (n + 1)))
by A2, A3, A4;
A6:
2 |^ ((n + 1) + n) = (2 |^ (n + 1)) * (2 |^ n)
by NEWTON:8;
A7:
n >= 1 + 1
by A1, NAT_1:13;
then
n + 1 >= 2 + 1
by XREAL_1:6;
then A8:
2 |^ (n + 1) >= 2 |^ 3
by PREPOWER:93;
A9:
2 |^ n >= 2 |^ 2
by A7, PREPOWER:93;
then
(2 |^ n) - 1 >= 4 - 1
by Lm1, XREAL_1:9;
then A10:
(2 |^ (n + 1)) * ((2 |^ n) - 1) >= 8 * 3
by A8, Lm2, XREAL_1:66;
then A11:
((2 |^ (n + 1)) * ((2 |^ n) - 1)) + 1 >= 24 + 1
by XREAL_1:6;
then
(((2 |^ ((2 * n) + 1)) - (2 |^ (n + 1))) + 1) * (((2 |^ ((2 * n) + 1)) + (2 |^ (n + 1))) + 1) >= 25 * (((2 |^ ((2 * n) + 1)) + (2 |^ (n + 1))) + 1)
by A6, XREAL_1:64;
then A12:
(1 / 5) * ((2 |^ ((4 * n) + 2)) + 1) >= (1 / 5) * (25 * (((2 |^ ((2 * n) + 1)) + (2 |^ (n + 1))) + 1))
by A5, XREAL_1:64;
reconsider L = ((2 |^ ((2 * n) + 1)) - (2 |^ (n + 1))) + 1 as Element of NAT by A6, A11;
(2 |^ n) + 1 >= 4 + 1
by A9, Lm1, XREAL_1:6;
then A13:
(2 |^ (n + 1)) * ((2 |^ n) + 1) >= 8 * 5
by A8, Lm2, XREAL_1:66;
then A14:
((2 |^ (n + 1)) * ((2 |^ n) + 1)) + 1 >= 40 + 1
by XREAL_1:6;
then
5 * (((2 |^ ((2 * n) + 1)) + (2 |^ (n + 1))) + 1) >= 5 * 41
by A6, XREAL_1:64;
then
2 <= 5 * (((2 |^ ((2 * n) + 1)) + (2 |^ (n + 1))) + 1)
by XXREAL_0:2;
hence
2 <= (1 / 5) * ((2 |^ ((4 * n) + 2)) + 1)
by A12, XXREAL_0:2; NUMBER02:def 1 not (1 / 5) * ((2 |^ ((4 * n) + 2)) + 1) is prime
A15:
(2 |^ ((4 * n) + 2)) + 1 = L * (((2 |^ ((2 * n) + 1)) + (2 |^ (n + 1))) + 1)
by A5;