OFFSET
0,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..5000
Index entries for linear recurrences with constant coefficients, signature (0, 0, 3, 0, 0, -3, 0, 0, 1).
FORMULA
Conjecture: a(n) = A046163(n), n>0. - R. J. Mathar, Jun 13 2008
a(n) = 3*a(n-3)-3*a(n-6)+a(n-9), with a(0)=1, a(1)=1, a(2)=7, a(3)=13, a(4)=7, a(5)=31, a(6)=43, a(7)=19, a(8)=73. - Harvey P. Dale, Apr 10 2014
EXAMPLE
a(4)=7 because 4^2+4+1 =21, the LCM of 3 and 21 is 21 and 21/3=7.
MAPLE
seq(denom((n-1)^2/(n^2+n+1)), n=0..52) ; # Zerinvary Lajos, Jun 04 2008
MATHEMATICA
Table[LCM[3, n^2+n+1]/3, {n, 0, 60}] (* or *) LinearRecurrence[ {0, 0, 3, 0, 0, -3, 0, 0, 1}, {1, 1, 7, 13, 7, 31, 43, 19, 73}, 60] (* Harvey P. Dale, Apr 10 2014 *)
PROG
(PARI) for(n=0, 50, print1(lcm(3, n^2 + n +1)/3, ", ")) \\ G. C. Greubel, Oct 26 2017
(Magma) [Lcm(3, n^2+n+1)/3: n in [0..50]]; // G. C. Greubel, Oct 26 2017
KEYWORD
easy,nonn
AUTHOR
W. Neville Holmes, Jul 14 2007
STATUS
approved