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

1,3

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

Table of n, a(n) for n=1..6.

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.

Sequence in context: A042681 A024243 A307094 * A013470 A013511 A013507

Adjacent sequences: A147771 A147772 A147773 * A147775 A147776 A147777

Keyword

more,nonn

Author

Alexander Adamchuk, Nov 12 2008

Status

approved