login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A025531 a(n) = (2nd elementary symmetric function of {1/1, 1/2, ..., 1/n})*(lcm(S))^2, where S = {1,2,...,n}. 1
2, 36, 210, 6750, 8120, 459620, 2067170, 20522250, 22318758, 2905171038, 3098543448, 554652370272, 584150230092, 612299943684, 2556925522866, 768804781750434, 797490150102074, 297862797402850394, 307475819473818710, 316760108055672710, 325739683035302510, 176916612931176848990 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Robert Israel, Table of n, a(n) for n = 2..1150

MAPLE

g:= gfun:-rectoproc({(-n^2-4*n-4)*s(n+1)+(3*n^2+15*n+19)*s(n+2)+(-3*n^2-18*n-27)*s(n+3)+(n^2+7*n+12)*s(n+4), s(0) = 0, s(1) = 0, s(2) = 1/2, s(3) = 1}, s(n), remember):

f:= n -> g(n)*ilcm($1..n)^2:

map(f, [$2..100]); # Robert Israel, Aug 10 2018

CROSSREFS

Sequence in context: A141217 A206688 A226419 * A099903 A074426 A082636

Adjacent sequences:  A025528 A025529 A025530 * A025532 A025533 A025534

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Offset corrected and more terms from Robert Israel, Aug 10 2018

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 21 19:04 EDT 2019. Contains 326168 sequences. (Running on oeis4.)