I'd been fooling around with a problem, and I had identified the constant C = 0.0676676416183063 (yes, actually to that kind of accuracy!) as being important in it.
The Inverse Symbolic Calculator doesn't recognize C as 1/(2e2). But it does recognize it as 1/(2 exp(√2)√2), and it told me that 10C was (√5)2/(e2).
I am a bit perplexed by why their tables would include these but not the more "obvious" form 1/(2e2).