High Quality Content by WIKIPEDIA articles! A Zeisel number, named after Helmut Zeisel, is a square-free integer k with at least three prime factors which fall into the patternThe name Zeisel numbers was probably introduced by Kevin Brown, who was looking for numbers that when plugged into the equationyield prime numbers. In a posting to the newsgroup sci.math on 1994-02-24, Helmut Zeisel pointed out that 1885 is one such number. Later it was discovered (by Kevin Brown?) that 1885 additionally has prime factors with the relationship described above, so a name like Brown-Zeisel Numbers might be more appropriate.