OFFSET
3,1
LINKS
Harry J. Smith, Table of n, a(n) for n = 3..1000
Tanya Khovanova, Recursive Sequences.
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
a(n) = (n-2)*180.
From Elmo R. Oliveira, Apr 17 2026: (Start)
G.f.: 180*x^3/(1 - x)^2.
E.g.f.: 180*((x - 2)*exp(x) + x + 2).
a(n) = 2*a(n-1) - a(n-2) for n > 4. (End)
EXAMPLE
a(3) = 180, since the sum of the interior angles in a triangle is 180 degrees.
MATHEMATICA
180 Range[36] (* Alonso del Arte, Sep 22 2017 *)
(* Alternative: *)
LinearRecurrence[{2, -1}, {180, 360}, 50] (* Harvey P. Dale, Apr 06 2022 *)
PROG
(PARI) a(n) = { (n - 2)*180 } \\ Harry J. Smith, Feb 03 2010
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Ulrich Schimke (ulrschimke(AT)aol.com), Dec 12 2001
STATUS
approved