mathematics - Which Flight Takes Me Home?

My vacation just ended, and I'm at the airport headed back home! It was definitely an enjoyable trip, but it could also be described as, well, unusual.

I've got a more immediate problem though. I've kind of forgotten which gate my flight arrives at. The answer is probably somewhere in the grid, but I can't see it. Could you help me out?

LOFCSURFTCZLRNTVZFUUNRBTON
JZTZODUJRTSCJCBFNOFSYSVZCJ
RFBYMBVRMSOYYLNMYYJCDLRFZB

Clarification: Gates are identified by a letter followed by a number.

Hint: 1:

Two words in the exposition are precisely chosen to be relevant.

Hint 2:

No, not primes.

Answer

Finally got it. The first important word, as we already knew, is "unusual", referring to unusual numbers. Since the hint says "not primes", we are interested in the sequence of not-prime unusual numbers, that goes like this:

6, 10, 14, 15, 20, 21, 22, 26, ...

These actually dictates

the valid letters in the grid by their number: F, J, N, O, T, U, V, Z

If we apply this knowledge to the grid, we get:

      O F     U   F T   Z     N T V Z F U U N     T O N
    J Z T Z O   U J   T     J     F N O F       V Z   J
      F         V       O       N       J         F Z  

I tried this ages ago but it didn't seem useful at all,

until @icke mentioned the Braille idea. If each letter is a dot, in Braille this reads:

   W H I T E K I N G P A W N

I guess this refers to

the most common chess opening, defined by the simple and ubiquitous move E4

and that's your gate.