42949672960domain: NAppears in sequencesa(n) = 10*4^n.at n=16A002066Fourth column of triangle A067410.at n=12A067412a(n) = 8*a(n-2) for n > 2; a(1) = 5, a(2) = 12.at n=22A164737Least k such that A006666(k)/A006667(k) = prime(n).at n=11A303811