193040domain: NAppears in sequencesn*10^5-1, n*10^5-3, n*10^5-7 and n*10^5-9 are all prime.at n=26A064979Analog of A060410 for the 7x+1 problem (cf. A133421).at n=7A133426Number of circular arrangements of the first n positive integers such that adjacent terms have absolute difference 1 or 4.at n=43A336749