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.

Showing 1-3 of 3 results.

A051752 Number of n X n (real) {0,1}-matrices having determinant A003432(n).

Original entry on oeis.org

1, 1, 3, 3, 60, 3600, 529200, 75600, 195955200, 13716864000
Offset: 0

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Crossrefs

Extensions

a(5) = 3600 from Daniel P. Corson (danl(AT)MIT.EDU), Jan 09 2000
a(6) = 529200, a(7) = 75600 from Ulrich Hermisson (uhermiss(AT)rz.uni-leipzig.de), Feb 25 2003
More terms from Miodrag Zivkovic (ezivkovm(AT)matf.bg.ac.yu), Feb 28 2006
a(0)=1 prepended by Alois P. Heinz, Dec 20 2023

A089478 Triangle T(n,k) read by rows, where T(n,k) = number of times the determinant of a real n X n (0,1)-matrix takes the value k, for n >= 0, 0 <= k <= A003432(n).

Original entry on oeis.org

0, 1, 1, 1, 10, 3, 338, 84, 3, 42976, 10020, 1200, 60, 21040112, 4851360, 1213920, 144720, 43560, 3600, 39882864736, 9240051240, 3868663680, 768723480, 418703040, 63612360, 46569600, 6438600, 5014800, 529200, 292604283435872
Offset: 0

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Author

Hugo Pfoertner, Nov 04 2003

Keywords

Comments

The first 4 rows were provided by Wouter Meeussen.

Examples

			a(4) = T(2,1) = 3 because there are 3 different (0,1)-matrices with determinant=1:
  ((1,0),(0,1)), ((1,1),(0,1)), ((1,0),(1,1)).
Triangle T(n,k) begins:
         0,       1;
         1,       1;
        10,       3;
       338,      84,       3;
     42976,   10020,    1200,     60;
  21040112, 4851360, 1213920, 144720, 43560, 3600;
  ...
		

Crossrefs

Cf. T(n,0) = A046747(n), T(n,1) = A086264(n), T(n,A003432(n)) = A051752(n).
The n-th row of the table contains A089472(n) nonzero entries.
Cf. A089479.

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Extensions

Edited by Alois P. Heinz, Dec 20 2023

A119008 Number of n X n real symmetric (0,1)-matrices with determinant = 1.

Original entry on oeis.org

1, 1, 4, 268, 9456, 301306, 24846368, 8946957244, 4175660906560, 2421067614753916
Offset: 1

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Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Extensions

a(8)-a(10) from Max Alekseyev, Jun 17 2025
Showing 1-3 of 3 results.