1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800
OEIS: A000142
Formula: factorial(n)
Serie: x/(1-x)
Actions: s[1], t*s[1, 1] + s[2], t*s[1, 1, 1] + (t^2+t)*s[2, 1] + s[3], t^2*s[1, 1, 1, 1] + (t^3+t^2+t)*s[2, 1, 1] + 2*t^2*s[2, 2] + (t^3+t^2+t)*s[3, 1] + s[4], t^2*s[1, 1, 1, 1, 1] + (t^4+2*t^3+t^2)*s[2, 1, 1, 1] + (t^4+2*t^3+2*t^2)*s[2, 2, 1] + (t^4+3*t^3+t^2+t)*s[3, 1, 1] + (t^4+2*t^3+2*t^2)*s[3, 2] + (t^4+t^3+t^2+t)*s[4, 1] + s[5], t^3*s[1, 1, 1, 1, 1, 1] + (t^5+2*t^4+t^3+t^2)*s[2, 1, 1, 1, 1] + (2*t^5+3*t^4+4*t^3)*s[2, 2, 1, 1] + (3*t^4+t^3+t^2)*s[2, 2, 2] + (t^5+5*t^4+3*t^3+t^2)*s[3, 1, 1, 1] + (3*t^5+6*t^4+5*t^3+2*t^2)*s[3, 2, 1] + (t^5+t^4+3*t^3)*s[3, 3] + (2*t^5+3*t^4+3*t^3+t^2+t)*s[4, 1, 1] + (t^5+4*t^4+2*t^3+2*t^2)*s[4, 2] + (t^5+t^4+t^3+t^2+t)*s[5, 1] + s[6]