Beam Equihash specification
N = 150
K = 5
Since 150 in not a multiple of 8 we pick 19 full bytes and clear lower 2 bits of 18th byte.
We can get only 3 hashes from 512-bit blake2 output.
Expected blake2 hash output size is
3 * 19 = 57 bytes
Beam’s Equihash implementation for CPU is based on zcash’s version. https://github.com/BeamMW/beam/blob/master/3rdparty/crypto/equihash_impl.cpp