21591162domain: NAppears in sequencesApproximation of the 2-adic integer arctanh(2) up to 2^n.at n=25A309753Approximation of the 2-adic integer arctanh(2) up to 2^n.at n=26A309753Approximation of the 2-adic integer arctanh(2) up to 2^n.at n=27A309753Approximation of the 2-adic integer arctanh(2) up to 2^n.at n=28A309753