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.

A127503 Number of n X n matrices A with 1's on the main diagonal and -1's and 0's elsewhere such that A + A' has only 0's and -1's off the main diagonal and is positive semi-definite.

Table of values

n a(n)
1 1
2 3
3 27
4 281
5 3945
6 70635
7 1437555
8 30357425
9 628337745

List of values

[1, 3, 27, 281, 3945, 70635, 1437555, 30357425, 628337745]

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

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