This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A205958 a(0) = 1 and a(n) = A180000(n)*a(floor(n/2))^2 for n > 0. 2
 1, 1, 1, 1, 2, 2, 3, 3, 48, 16, 40, 40, 270, 270, 945, 63, 129024, 129024, 64512, 64512, 2016000, 96000, 528000, 528000, 144342000, 28868400, 187644600, 20849400, 1787836050, 1787836050, 59594535, 59594535, 3999321544458240, 121191561953280, 1030128276602880 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS lcm(1,2,..,n) = (n!*a(n)) / ((n/2)!*a(n/2))^2. lcm(1,2,..,n)*a(n) is a divisor of n! and n!/(lcm(1,2,..,n)*a(n)) is a square. LINKS PROG (Sage) def A205958(n) :     if n == 0 : return 1     return A180000(n)*A205958(n//2)^2 CROSSREFS Cf. A180000, A025527, A205959. Sequence in context: A053094 A196080 A124516 * A309090 A091048 A071478 Adjacent sequences:  A205955 A205956 A205957 * A205959 A205960 A205961 KEYWORD nonn AUTHOR Peter Luschny, Feb 04 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 14 18:28 EDT 2019. Contains 328022 sequences. (Running on oeis4.)