OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 877
FORMULA
a(n) = 2*a(n-1) - a(n-2) + a(n-3) - a(n-4) (holds at least up to n = 1000 but is not known to hold in general).
Empirical g.f.: (3-x+x^2-2*x^3)/(1-x)/(1-x-x^3). [Colin Barker, Feb 19 2012]
MATHEMATICA
RecurrenceTable[{a[0] == 3, a[1] == 5, a[n] == Floor[a[n - 1]^2/a[n - 2]]}, a, {n, 0, 50}] (* Bruno Berselli, Feb 04 2016 *)
PROG
(Magma) Iv:=[3, 5]; [n le 2 select Iv[n] else Floor(Self(n-1)^2/Self(n-2)): n in [1..50]]; // Bruno Berselli, Feb 04 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved