From

A Handbook of Integer Sequences :

This number sequence is related to the famed Fibonacci numbers, but rather than have numbers that are the sum of the two preceding numbers, how 'bout numbers that are the sum of the three preceding numbers? It goes a little something like this...

**1, 1, 2, 4, 7, 13, 24, 44, 81, 149, 274, 504, 927...**

Again, I leave the challenge of showing how this can be applied to the real world to someone far wiser than I.