herb wilf had an office in the stanford computer science building (margaret jacks hall) ca 1986 or 1987 or so. he was probably on sabbatical. his office wasn't too far away from my grad student cube farm and i got to know him a tiny bit. he told me about some problems having to do with symmetric chain decompositions of posets he also posed a generating functions problem later known as "n coins in a fountain" on my analysis of algorithms qualifying exam. A005169 - OEIS is relevant anyway, one day three people were walking in a line toward the front door of margaret jacks hall. the first person was herb wilf. the second person, following wilf about ten paces behind, was campus celebrity joe euclid (see link below). but i'm sure wilf didn't know about euclid. the third person, ten paces behind euclid, was me. with this staging of dramatis personae, events unfolded as follows wilf reaches the door of margaret jacks hall. as he opens the door, he notices euclid, following behind him holding a huge stack of papers. wilf pauses at the door, propping it open nicely for euclid. but euclid does not go in. instead, he pauses right in front of wilf. WILF: May I help you? EUCLID: Well, I suppose the FIRST THING IS, why doesn't ANYONE believe UFOS ARE REAL!!!!! (this last part almost screaming). I had the pleasure of slipping into the building and smiling at Wilf as I went through the door still being held open by him http://en.wikipedia.org/wiki/Joe_Jonah_Euclid -- Thane Plambeck tplambeck@gmail.com http://counterwave.com/