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Problems & Puzzles: Puzzles

Puzzle 1273 A follow-up to Puzzle 068

During May 2026, Roberto Angelone sent a new Magic Square record for the Puzzle 68

 

As you may read, he constructed a 729x729 Magic squares that he claims is composed only for distinct primes, and some other properties that are irrelevant for the purposes of this puzzle 68.

If you do me the favor of going to the puzzle 68 page, you will find the rest of the story behinds this 729x729 Angelone's magic square.

Q1. Are there published MS composed by only distinct prime numbers greater than the Angelone's one?

Q2. Can you verify that all these 729x729 cells are filled with only distinct prime numbers?



 




From June 26 to July 4, contributions came from Michael Branicky, Paul Cleary, Roberto Angelone

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Michael wrote:
All 729x729 elements in the MS are prime. I also verified that all row sums, columns sums, and diagonal and anti-diagonal sums are the same: 7290000024057
For ease of future studies, I attach a clean .csv file with 729 rows and 729 columns where each entry is a plaintext integer (with no comma-for-thousands separators). It is 5.9MB.

Michael added: For reference, attached is a short Python program to perform the verification on the clean csv file.

(Note by CR: My plan is not to upload both files sent by Michael. I will keep just in my local site, ready to send it to anyone who ask for it, on request by email.)
***
Paul wrote:

Q1.  I found this if you could call it published..
Q2.  All entries are distinct prime numbers.

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Roberto Angelone wrote:

On July 2, 2026, he announced larger prime MS, and perhapas a new record in this subject:
6561x6561 Consecutive primes found on:  https://zenodo.org/records/20417121. You need to scroll down to the specific file called "07-6561X6561-CONSECUTIVE-PRIMES.csv".  and 2187x2187 3^n Nested Primes found on:  https://zenodo.org/records/20385047 and similarly scroll down to the either the file called "MASTER BLOCK-MATHS_2187x2187_assembled_unique_prime_magic_square.csv" or the one below it called "MASTER BLOCK-MATHS_2187x2187_assembled_unique

After downloading his Excel version of the MS 6561x6561, this is what I could verify:

MS 6561x6561, According  R. Angelone 2678155179653
My findings, CBRF, Julio 2, 2026
Central Cell (Row 3281 y Col = DVE) = 403798981
Quantity of rowand Columns = 6561
Product if the Central Cell by 6551= 2649325114341
Max Prime 839097031
Min Prime 44381
Quantity of primes between Min Prime & Max prime = 43046721
Quantity of Cells = 43046721
I haven't been able to confirm that all the cells are distinct  
I haven been able to confirm the MS in the 2x6561+2 zones (rows, columns and main diagonals)


But the most intriguing feature is that 6561 x the value of the Central Cell is (2649325114341) not equal to the MS (2678155179653), Is this correct or incorrect?

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M.F. Hasler wrote on July 9, 2026:

I have looked at https://www.primepuzzles.net/puzzles/puzz_1273.htm
First, I have downloaded the 729 x 729 CSV file.
I can confirm that it is made of 729² distinct primes.

I have also downloaded "06-2187X2187-CONSECUTIVE-PRIMES.csv" from https://zenodo.org/records/20417121
I have checked that all rows have distinct primes in it,
row, column & diagonal sums are 87047577443,
smallest and largest primes are
p = 24419 = prime(2711), and q = 82113467 = prime(4785679).
Since primepi(q) - primepi(p) = 4782968 = 729² - 1
it is indeed most likely that the matrix is made of exactly all consecutive primes from p to q.

Then this is indeed a new record magic square, until the one of size 6561² is verified. I did not yet verify the 6561² square, because I hesitate to download the 424 MB file [and then process it ...].

But looking at your comments: you are surprised that
Product if the Central Cell by 6551 = different from row sums.
Note, there are two typos :"if" => "of", "6551" => 6561.

But, the fact is not surprising. For example, in the 2187 x 2187 magic square,
the central value is 58061, which multiplied by 2187 gives only 126979407
while all row & column sums are 87047577443.

- Maximilian

/* PARI/GP code, for my records */
check(fn="/Users/mh/Downloads/06-2187X2187-CONSECUTIVE-PRIMES.csv")={
my(f=fileopen(fn), m=oo, M=0/*min & max*/, diagsum=0, antids=0, rows=0,
rowsum, colsum, row); while( row=filereadstr(f), print1(".");
if( !row=eval(Str("["row"]")),/*empty row*/ next,
rows++&& !M,/*initialize*/ rowsum=vecsum(colsum=row),
rowsum != vecsum(row), error("bad sum in row "rows),
colsum += row /*=> error if different length*/)/*end if*/;
diagsum += row[rows]; antids += row[#row-rows+1];
if(#row != #row=Set(row), error("duplicates in row "rows);
/* update min / max */ row[1]<m, m=row[1] );/*end if*/
row[#row]>M && M=row[#row];/*both can happen in the same row!*/
foreach(v, p, ispseudoprime(p)|| error("Nonprime "p" in row "rows));
)/*end while*/; fileclose(f);
[m, M, rowsum, rowsum-diagsum, rowsum-antids, Set(colsum)-[rowsum]] }

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