A147774 Number of equivalence classes of normalized Hadamard matrices of order 4n with respect to permutations of rows and columns.

1, 1, 2, 118, 6520, 43966313

Offset: 1

Author

Alexander Adamchuk, Nov 12 2008

Keywords

• more
• nonn

Comments

Number of equivalence classes N(k) = {1, 1, 1, 1, 2, 118, 6520, 43966313} for order k = {1, 2, 4, 8, 12, 16, 20, 24}, (see Theorem 2 at the Hadamard matrices project results link). Note that N(24) = a(6) = 43966313 is a prime.

Links

• Hadamard Matrices Project. Results (in Russian) [broken link]
• Eric Weisstein's World of Mathematics, Hadamard Matrix

Crossrefs

Cf. A007299 = Number of Hadamard matrices of order 4n.