667776domain: NAppears in sequencesa(n) contains n digits (either '6' or '7') and is divisible by 2^n.at n=5A053337Smallest multiple of A047201(n) (i.e., numbers not divisible by 5) with only digits 6 and 7.at n=37A124476Valid groups of final digits a square number made entirely of the digits 6, 7 and 8 can have.at n=17A241072