Hi and welcome to the MPC forums.
The easiest way to get what you want is use the circuit in the link. It would be the second circuit down on the web page. The circuit is called "Another Variation" and uses a 555 timer to clock a 4017 decade counter / divider chip. The 4017 is set up to count to N and recycle. Thus it produces the LED effect seen below the schematic. The downside is you only get 10 LEDs in a sequence.
Now if you want 16 LEDs to run in a similar sequence it can be done by modifying the first circuit shown. It would require fewer chips too!
You lost me with the reference to using Pspice? Pspice is simulator software frequently used within the Orcad family. The drawing is done in Orcad Capture and the Simulation run in Pspice.
Short of using a PIC uC (Micro Controller) and programming it what you see on that web page is about the simplest way to sequence LEDs.
Note of importance 2/25/06
The pin out of the 74154 chip in the above image is incorrect. This just came to my attention. Note that pin 14 is shown as common and again shows up as an output (Y12). Pin 14 of this chip is not common. Pin 12 is common of this chip. I suggest using the link for the PDF file on this chip located below. Many thanks to a Maximum PC forum reader for bringing this to my attention. As time allows I will get a new and correct drawing posted to this page. Additionally I found an excellent rendition of this same circuit including a parts list here.
Therefore you should be able to redraw the schematic in Capture and modify it for your desired effect then run the simulation in Pspice.
Additionally this does not belong in the Windows Parlor so it will be moved. I just don't know where?
Maybe Hardware haven or modding sections?