Well, the reason I’m asking is because I’m gonna setup a set of memory palaces to solidify my 3-digit system. I’ve done this before by placing my old PAO major system into 7 separate memory palaces linked to the year codes for calendar calculation.
Sidebar: I’ve seen in other posts that you are still trying to get a solid grip on your major system… maybe the year codes approach will work for you too. The nice thing is that you constantly use the lookup of your major images even though you are technically doing calculations, so it becomes more of a background task.
The setup for the primes would be like this… taking only up to 1,000 instead of 10,000 to make it easier to read:
0 [20, 32, 51, 53, 62, 84, 89]
1 [18, 21, 24, 42, 63, 66, 69, 81]
2 [11, 29, 68, 74, 77, 86, 95, 98]
3 [28, 52]
4 [9, 12, 30, 36, 39, 45, 48, 55, 58, 72, 78, 79, 87, 90, 93, 96]
5 [3, 6, 15, 25, 27, 33, 54, 57, 60, 75, 94, 97, 99]
6 [16, 67]
7 [4, 31, 46, 64, 88]
8 [14, 41, 47, 71, 80, 83, 92]
9 [40, 49, 70, 76, 91]
10 [2, 5, 8, 17, 23, 26, 35, 37, 38, 44, 50, 56, 59, 65, 73]
11 [7, 43]
12 [34]
13 [13]
14 [22, 61, 85]
15 [1, 10, 19, 82]
I’m using a bit-mask for the last digit, where 0000 corresponds to 9731. It’s the same logic used when doing chmod 777 (Understanding File Permissions: What Does "Chmod 777" Mean? - Make Tech Easier). Basically, it works like this:
- get a number xyz (343) or later wxyz
- drop the last digit z (3) from xyz or later wxyz
- look up the decade xy (34 = MR = image) in the palace set
- convert the decade's palace from base10 (12) to base2 (1100)
- apply this mask to 9731 (97##); these are the primes: 349 and 347
So now you know that the decade (seems like a sensible name) only has primes ending in 9 and 7 (i.e., 349 and 347), so 343 is not a prime. Up to 16 I have no problem converting between decimal, binary, and hex, so I won’t lose any time there. It will cover all my images up to 999 except for 000 because the single digit primes (2, 3, 5, 7) don’t fit the pattern.
In the end, it’s 16 palaces with half as many loci as there are items, if I put two images per location. The bigger palaces will be subdivided into more manageable sizes about the size of the smaller palaces. In the end, the whole thing will look like this:
0 218 items
1 106 items
2 104 items
3 25 items
4 108 items
5 94 items
6 25 items
7 16 items
8 104 items
9 25 items
10 95 items
11 15 items
12 21 items
13 14 items
14 18 items
15 11 items
I won’t be able to show off by recalling all primes in order but lookup will be almost instantaneous: drop the last digit, find which palace that image is in, and see if the mask allows for the dropped digit.
Still looking for a set of palaces that works with 16… at the moment I’m considering the list of German states by area but not completely convinced it’s the best set of 16. It would be easy enough though to find a route with enough locations in each state’s capital.
ps: would still be nice though if I could do more with it than know whether a number is prime or not.