OEIS A229580 mini challenge (RPL)

[Joe Horn]

Oh dear... 81 bytes, same answers for 1 and 30, but 0.0989_s for 30. I used a local variable and an algebraic expression. I suspect that you wrote it using only the stack. I gotta see that.

EDIT: Rewrote using just the stack, but it only shrank to 50 bytes, and takes 0.0792_s for an input of 30. Hmmmm.....

EDIT 2: Down to 47.5 bytes, 0.0778_s for an input of 30. You are keeping me up all night!