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N-numbers were used in A Handbook of Integer Sequences, which contains 2372 sequences in lexicographic order which are assigned numbers from 1 to 2372. It only includes sequences of nonnegative integers, sequences containing negative numbers being replaced by their absolute values. Only infinite (or conjectured to be, e.g. Mersenne primes) sequences are included. The lexicographic order is defined by omitting all initial 0's and 1's and replacing them by a single 1. The initial 1 is added even if it was not in the original sequence. The The Encyclopedia of Integer Sequences includes the references to the corresponding sequences (which may differ in their few initial terms) in A Handbook of Integer Sequences as N-numbers from N0001 to N2372 (instead of 1 to 2372.)