Proof step

Ore-algebra identity of two definitions

All-n equality of two definitions

Concludes

shift_x_plus_one of gamma_polynomial of Triangle T(n, k) is coefficient of z^n*w^k in 1/(1 - 2*z - 2*w - 2*z*w) read by rows in order 00, 10, 01, 20, 11, 02, .…

Premises

none: a direct theorem check

Theorem

polytool ?

Checked

polytool replayed · Lean not attempted