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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A210640 a(n) = least integer m > 1 such that 2S_k^2 (k=1,...,n) are pairwise distinct modulo m, where S_k is the sum of the first k primes.

Table of values

n a(n)
1 2
2 4
3 9
4 13
5 17
6 28
7 37
8 37
9 37
10 37
11 37
12 61
13 61
14 61
15 151
16 151
17 151
18 151
19 151
20 151
21 151
22 227
23 227
24 227
25 227
26 227
27 307
28 307
29 307
30 337
31 433
32 433
33 433
34 433
35 433
36 433
37 433
38 433
39 433
40 433
41 433
42 509
43 509
44 509
45 509
46 509
47 643
48 727
49 727
50 761
51 761
52 761
53 971
54 971
55 971

List of values

[2, 4, 9, 13, 17, 28, 37, 37, 37, 37, 37, 61, 61, 61, 151, 151, 151, 151, 151, 151, 151, 227, 227, 227, 227, 227, 307, 307, 307, 337, 433, 433, 433, 433, 433, 433, 433, 433, 433, 433, 433, 509, 509, 509, 509, 509, 643, 727, 727, 761, 761, 761, 971, 971, 971]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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