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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.

A192702 Number of 3X3 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 3 zero-sum 3-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).

Table of values

n a(n)
1 2
2 9
3 36
4 114
5 308
6 745
7 1597
8 3194
9 5944
10 10408
11 17408
12 28207
13 43739
14 66091
15 97417
16 139756
17 197048
18 273225
19 370834
20 497159
21 658332
22 859295
23 1109567
24 1420234
25 1795384
26 2253449
27 2806737
28 3464221
29 4246712
30 5179322
31 6262896
32 7537671
33 9025226

List of values

[2, 9, 36, 114, 308, 745, 1597, 3194, 5944, 10408, 17408, 28207, 43739, 66091, 97417, 139756, 197048, 273225, 370834, 497159, 658332, 859295, 1109567, 1420234, 1795384, 2253449, 2806737, 3464221, 4246712, 5179322, 6262896, 7537671, 9025226]

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

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