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.

A234471 Number of sets of 4 distinct collinear points in an n X n permutation array in which leftmost pair has same spacing as rightmost pair.

Table of values

n a(n)
1 0
2 0
3 0
4 2
5 10
6 30
7 86
8 180
9 344
10 624
11 1056
12 1626
13 2522
14 3646
15 5118
16 7164
17 9784
18 12868
19 16848
20 21438
21 27202
22 34298
23 42550
24 51800
25 63184
26 76256
27 91032
28 108086
29 127850
30 149442
31 174902
32 202552
33 233608
34 268512
35 306664
36 349394
37 398226
38 450510
39 507038
40 569204

List of values

[0, 0, 0, 2, 10, 30, 86, 180, 344, 624, 1056, 1626, 2522, 3646, 5118, 7164, 9784, 12868, 16848, 21438, 27202, 34298, 42550, 51800, 63184, 76256, 91032, 108086, 127850, 149442, 174902, 202552, 233608, 268512, 306664, 349394, 398226, 450510, 507038, 569204]

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

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