

A099946


a(n) = lcm{1, 2, ..., n}/(n*(n1)), n >= 2.


2



1, 1, 1, 3, 2, 10, 15, 35, 28, 252, 210, 2310, 1980, 1716, 3003, 45045, 40040, 680680, 612612, 554268, 503880, 10581480, 9699690, 44618574, 41186376, 114406600, 106234700, 2868336900, 2677114440, 77636318760, 145568097675, 136745788725
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OFFSET

2,4


LINKS

Luke March and Alois P. Heinz, Table of n, a(n) for n = 2..1000 (first 99 terms from Luke March)


FORMULA

a(n) = A003418(n)/(n*(n1)) = A003418(n)/A002378(n1), n >= 2.


MAPLE

a:= n> ilcm(seq(k, k=1..n))/n/(n1): seq(a(n), n=2..37); # Emeric Deutsch, Jun 13 2005


MATHEMATICA

Table[LCM@@Range[n]/(n(n1)), {n, 2, 40}] (* Harvey P. Dale, Jan 14 2011 *)


PROG

(Python)
from fractions import gcd
def lcm(a, b): return (a*b)/gcd(a, b)
def f(lim):
....l=1
....for x in range(2, lim+1):
........l=lcm(x, l)
........print x, l/(x*(x1))
f(100) # Luke March, Jul 23 2014
(PARI) a(n) = lcm(vector(n, i, i))/(n*(n1)); \\ Michel Marcus, Jul 25 2014


CROSSREFS

Cf. A002378, A002944, A003418, A025558.
Sequence in context: A327809 A075856 A025520 * A011953 A038519 A192617
Adjacent sequences: A099943 A099944 A099945 * A099947 A099948 A099949


KEYWORD

nonn,easy,changed


AUTHOR

N. J. A. Sloane, Nov 12 2004


EXTENSIONS

More terms from Emeric Deutsch, Jun 13 2005


STATUS

approved



