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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.

A114530 a(n) = permanent of a bordered n X n (1,-1)-matrix with the following property: the elements on the border are 1; if we concatenate the rows of the matrix to form a vector v of length n^2, v_i = -1 if i is not a prime. The border of a matrix consists of the first and the last row and the first and the last column.

Table of values

n a(n)
3 6
4 0
5 8
6 144
7 -80
8 -384
9 -2816
10 -15360
11 -125184
12 5322240
13 -22966272
14 36771840
15 -887224320
16 1488936960
17 -217760382976
18 -1484266291200
19 -45948014198784
20 65021593190400
21 -3267216288645120
22 -856122753024000
23 -3180322010587725824

List of values

[6, 0, 8, 144, -80, -384, -2816, -15360, -125184, 5322240, -22966272, 36771840, -887224320, 1488936960, -217760382976, -1484266291200, -45948014198784, 65021593190400, -3267216288645120, -856122753024000, -3180322010587725824]

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

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