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.

A057982 Number of singular n X n (-1,1)-matrices.

Original entry on oeis.org

0, 8, 320, 43264, 22003712, 43090149376, 326720427917312, 9588057159626653696, 1086099857128493963804672
Offset: 1

Views

Author

Eric W. Weisstein, Oct 23 2000

Keywords

Comments

a(n) = 2^(2n-1)*A046747(n-1). - Kevin Costello, May 18 2005

Crossrefs

Complement of A056990.
Cf. A046747.

Formula

a(n)/2^(n^2) ~ (1/2 + o_n(1))^n (proved by Tikhomirov). - Timothy Y. Chow, Jan 17 2019

Extensions

More terms from Kevin Costello, May 18 2005
a(6)-a(9) from Herman Jamke (hermanjamke(AT)fastmail.fm), Apr 18 2008