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.

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A335776 Number of idempotent non-symmetric n X n (0,1)-matrices over the reals.

Original entry on oeis.org

0, 0, 4, 42, 436, 5650, 96544, 2185610, 65108236
Offset: 0

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Author

Torlach Rush, Jun 22 2020

Keywords

Comments

Off diagonal entries of an idempotent symmetric n X n (0,1)-matrix must be zero.

Examples

			a(2) = 4 because [1,1]  [0,1]  [0,0]  [1,0]
                 [0,0], [0,1], [1,1], [1,0], are non-symmetric and idemponent.

Crossrefs

Cf. A000079, A086922.

Formula

a(n) = A086922(n) - A000079(n).
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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