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.

A063073 Square of determinant of character table of the dihedral group with 2n elements.

Original entry on oeis.org

4, 256, 36, 4096, 500, 82944, 9604, 2097152, 236196, 64000000, 7086244, 2293235712, 250994068, 94450499584, 10251562500, 4398046511104, 474351505988, 228509902503936, 24524265031204, 13107200000000000
Offset: 1

Views

Author

Ahmed Fares (ahmedfares(AT)my-deja.com), Aug 03 2001

Keywords

Comments

For any finite group G with order n we have that if A is the character table then |det(A)|^2 = product i (n/c(i)) where the product is over the conjugacy classes of G: c(i), so by this formula the square of the determinant is an integer (in the case of dihedral groups the characters are real).

Programs

  • PARI
    { for (n=1, 200, if (n%2, a=4 * n^((n+1)/2), a=64 * n^((n+2)/2)); write("b063073.txt", n, " ", a) ) } \\ Harry J. Smith, Aug 16 2009

Formula

a(n) = 4 * n^((n+1)/2) if n odd, a(n)= 64 * n^((n+2)/2) if n even. - Paul Boddington, Oct 22 2003

Extensions

Missing term included and more terms added by Harry J. Smith, Aug 16 2009