OFFSET
1,3
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,3,0,0,0,-3,0,0,0,1).
FORMULA
a(n) = A152018(n)/9.
a(1)=1, a(2)=1, a(3)=9, a(4)=2, a(5)=25, a(6)=9, a(7)=49, a(8)=8, a(9)=81, a(10)=25, a(11)=121, a(12)=18, a(n)=3*a(n-4)-3*a(n-8)+a(n-12). - Harvey P. Dale, Aug 25 2013
Conjecture: a(n) = denominator((n-2)^3/n^2). - Andres Cicuttin, Sep 19 2017
a(n) = n^2/gcd(n^2, 8). - Andrew Howroyd, Jul 25 2018
Sum_{n>=1} 1/a(n) = Pi^2/3 (A195055). - Amiram Eldar, Sep 14 2022
MATHEMATICA
Denominator[8/(9*Range[50]^2)]/9 (* or *) LinearRecurrence[{0, 0, 0, 3, 0, 0, 0, -3, 0, 0, 0, 1}, {1, 1, 9, 2, 25, 9, 49, 8, 81, 25, 121, 18}, 50] (* Harvey P. Dale, Aug 25 2013 *)
PROG
(PARI) a(n) = denominator(8/(9*n^2))/9 \\ Michel Marcus, Jun 01 2013
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Paul Curtz, Nov 20 2008
EXTENSIONS
More terms from Michel Marcus, Jun 01 2013
Keyword:mult added by Andrew Howroyd, Jul 25 2018
STATUS
approved