cp's OEIS Frontend

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.

A187529 Number of 3X3 0..n arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under 90 degree rotation.

Table of values

n a(n)
1 0
2 8
3 74
4 280
5 784
6 1970
7 3580
8 6946
9 11726
10 19100
11 27672
12 44092
13 58988
14 83340
15 116344
16 156470
17 193434
18 262028
19 316330
20 414216
21 517530
22 629058
23 735548
24 935702
25 1100836
26 1299196
27 1530340
28 1835766
29 2068728
30 2511536
31 2794280
32 3249058
33 3723336

List of values

[0, 8, 74, 280, 784, 1970, 3580, 6946, 11726, 19100, 27672, 44092, 58988, 83340, 116344, 156470, 193434, 262028, 316330, 414216, 517530, 629058, 735548, 935702, 1100836, 1299196, 1530340, 1835766, 2068728, 2511536, 2794280, 3249058, 3723336]

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

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