Sequence from Stan Wagon's Macalester POW #1060

[N. J. A. Sloane]

Joshua asks:
Given k coins, s of which are heavy,
...

Me: Just some background information:
this is the subject called "weighing designs",
and I have written some papers on it myself (there
are applications to spectroscopy)

The famous old book on the subject is by Banerjee.

A more modern book is Du and Hwang, Combinatorial Group Testing
and Its Applications, World Scientific 2000

Neil Sloane