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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.

A270775 a(n) is the number of invertible 2 X 2 upper triangular matrices over Z_p where p = prime(n).

Table of values

n a(n)
1 2
2 12
3 80
4 252
5 1100
6 1872
7 4352
8 6156
9 11132
10 22736
11 27900
12 47952
13 65600
14 75852
15 99452
16 143312
17 198476
18 219600
19 291852
20 347900
21 378432
22 480636
23 558092
24 689216
25 893952
26 1010000
27 1071612
28 1202252
29 1271376
30 1417472
31 2016252
32 2213900
33 2533952
34 2647116
35 3263696

List of values

[2, 12, 80, 252, 1100, 1872, 4352, 6156, 11132, 22736, 27900, 47952, 65600, 75852, 99452, 143312, 198476, 219600, 291852, 347900, 378432, 480636, 558092, 689216, 893952, 1010000, 1071612, 1202252, 1271376, 1417472, 2016252, 2213900, 2533952, 2647116, 3263696]

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

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