OFFSET
1,2
LINKS
FORMULA
Prod_{k=1}^{n} ((q^k - 1) / (q - 1)).
a(1) = 1, a(n) = ((-11)^n - 1) * a(n-1)/(-12). - Vincenzo Librandi, Oct 26 2012
MATHEMATICA
RecurrenceTable[{a[1]==1, a[n]==(((-11)^n - 1) a[n-1])/(-12)}, a, {n, 15}] (* Vincenzo Librandi, Oct 26 2012 *)
PROG
(Magma) [n le 1 select 1 else ((-11)^n - 1)*Self(n-1)/(-12): n in [1..13]]; // Vincenzo Librandi, Oct 26 2012
CROSSREFS
KEYWORD
sign,easy
AUTHOR
STATUS
approved