OFFSET
0,2
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,0,12).
FORMULA
a(n+1) = a(n) * A052901(n).
A001222(a(n)) = n.
a(n) = 12^floor(n/3)*(r+1)*(r+2)/2 with r = n mod 3. G.f.: -(6*x^2+3*x+1) / (12*x^3-1). - Alois P. Heinz, Apr 05 2012
Sum_{n>=0} 1/a(n) = 18/11. - Amiram Eldar, Feb 13 2023
MATHEMATICA
FoldList[Times, 1, PadRight[{}, 30, {3, 2, 2}]] (* Harvey P. Dale, Mar 19 2013 *)
PROG
(Haskell)
a208131 n = a208131_list !! n
a208131_list = scanl (*) 1 $ a052901_list
-- Reinhard Zumkeller, Mar 29 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Apr 04 2012
STATUS
approved