Wikipedia:Sandbox

A333330 2*n! 13 2, 2, 4, 12, 48, 240, 1440, 10080, 80640, 725760, 7257600, 79833600, 958003200, 12454041600, 174356582400, 2615348736000, 41845579776000, 711374856192000, 12804747411456000, 243290200817664000, 4865804016353280000 (list; graph; refs; listen; history; text; internal format) OFFSET 0,1 LINKS Table of n, a(n) for n=0..20. CROSSREFS For n![k]n!: (where [k] is the hyperoperation) A038507 (k=0), this sequence (k=1), A001044 (k=2), A046882 (k=3). For k=4, this is the Pickover’s superfactorial. Sequence in context: A287604 A007181 A100238 * A208529 A212660 A098774 Adjacent sequences: A333327 A333328 A333329 * A333331 A333332 A333333 KEYWORD nonn,changed AUTHOR Derek Schulze, Mar 14 2020 STATUS editing