24306922095domain: NAppears in sequencesSmallest k such that k^2+1 is divisible by A002144(n)^9.at n=2A145873a(n) is smallest number such that a(n)^2 + 1 is divisible by 17^n.at n=9A218710One of the two successive approximations up to 17^n for 17-adic integer sqrt(-1). Here the 13 (mod 17) case (except for n=0).at n=9A286878