a new puzzle sequence

[N. J. A. Sloane]

I'm baffled. Each of these, by itself, has many hits, but even most
pairs have nothing in common, modulo OEIS.

For example, 408 is Pell, Octagonal, 5-almost prime, sum of 3 positive cubes...

571 is prime of form 4n+3, prime of form 6n+1, greater of twin primes,
centered triangular, index of prime Fibonacci...

There are no obvious similarities beyond 3-digit-hood.

Could be a Word problem, or refer to something external (dates,
molecular weights, racehorses, whatever).

So, if a valid non-erroneous puzzle, I say it's a good one.