81905domain: NAppears in sequencessech(tanh(x)*cos(x))=1-1/2!*x^2+25/4!*x^4-1057/6!*x^6+81905/8!*x^8...at n=4A012692Base-5 digits are, in order, the first n terms of the periodic sequence with initial period 1,0,1.at n=7A033123Sums of 5 distinct powers of 5.at n=32A038477