It still boils down to the simple question...
What is your K values in? byte or bit you never specified. That is very important as there is an 8X difference between the two.
Assuming your requests are in BYTES...
If it's in bytes then 64KB (524288-bits) will barely fit in the 1,081,344-437,312 leftover configuration flash. But the problem is your memory requirement of 16KB (131072-bits), which won't fit in the 50AN as there are only 54Kb (55296-bits) of block RAM in the device. You will have to use an external SRAM to have that much memory.
When posting on a forum you must explicitly state all information, otherwise you're wasting everyone's time trying to extract REQUIRED information from you so we can help.