5-uples of practical numbers


A 5-uple of practical numbers is a 5-uple (m-6, m-2, m, m+2, m+6) of numbers, all practicals. It is unknown whether there exist infinitely many such 5-uples. This list shows practical numbers m such that m-6, m-2, m+2, and m+6 are practical.

Table no. 1

1 18
2 30
3 198
4 306
5 462
6 1482
7 2550
8 4422
9 17298
10 23322
11 23550
12 40350
13 52578
14 67938
15 88506
16 92202
17 96222
18 123006
19 131070
20 219102

Table no. 2

21 226182
22 237690
23 277506
24 312702
25 359658
26 432822
27 526878
28 533370
29 584166
30 659934
31 1032858
32 1051650
33 1140414
34 1142658
35 1243170
36 1255422

(Giuseppe Melfi - melfi@dm.unipi.it)

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