2687489280domain: NAppears in sequencesa(0)=0, a(1)=4; for n > 1, a(n) = 18*a(n-1) - a(n-2) + 8.at n=8A132584a(n) = sinh^2( 2n*arcsinh(sqrt n)).at n=4A173175Numbers k such that k and k+1 are both antiharmonic numbers (A020487).at n=24A335389