Scrypt-Adaptive-Nfactor (Scrypt-N) is a type of protection, the principle of which is to rationalize memory. Thus, Scrypt-N relies on the so-called adaptive N-factor, the memory that is required to perform new hashing functions. The memory requirement increases over time, making the use of ASICs impractical — that is, the coin is protected from ASIC-based miners who can easily centralize mining.
Using Scrypt-Adaptive-Nfactor allows mining to be more distributed because hardware is widely available when using this algorithm. The Scrypt-N algorithm was first used in the Vertcoin cryptocurrency.