[math-fun] Killing Fibonacci's Rabbits

If Fibonacci had used more realistic assumptions (ie his rabbits dying) he would have produced the Padovan (or Perrin?) sequence. http://matheminutes.blogspot.com.au/2012/02/killing-fibonaccis-rabbits.html Another example of this sort of thing; summing A000079 (powers of 2), and subtracting previous terms 2 generations back gives A003945 Is there a general form for such sequences?