1072000domain: NAppears in sequencesa(n) = 100^[n/10] + 2*n*10^[n/10]: inspired by Engel expansion of Pi.at n=36A137507G.f. A(x) satisfies: A(x) = ((1 + x)/(1 - x)) * A(x^2)^2*A(x^3)^3*A(x^4)^4* ... *A(x^k)^k* ...at n=17A307606E.g.f. A(x) satisfies A(x) = 1/( 1 - A(x) * sinh(x * A(x)) ).at n=6A381177