n-th derivative of x^(x^(x^x)) at x=1.

Terms

a(0) =1a(1) =1a(2) =2a(3) =9a(4) =56a(5) =360a(6) =2934a(7) =26054a(8) =269128a(9) =3010680a(10) =37616880a(11) =504880992a(12) =7387701672a(13) =115228447152