6139557domain: NAppears in sequencesSuccessive approximations to 5-adic integer sqrt(-1).at n=9A034935One of the two successive approximations up to 5^n for the 5-adic integer sqrt(-1).at n=10A048898a(n) is the unique odd-valued residue modulo 5^n of a number m such that m^2+1 is divisible by 5^n.at n=9A259266