OFFSET
0,3
LINKS
Guo-Niu Han, Enumeration of Standard Puzzles, 2011. [Cached copy]
Guo-Niu Han, Enumeration of Standard Puzzles, arXiv:2006.14070 [math.CO], 2020.
Index entries for linear recurrences with constant coefficients, signature (5,-4).
FORMULA
a(n) = n for n < 2, a(n) = 2^(2*n - 3) + 1 = A087289(n-2) for n >= 2. - Antti Karttunen, Oct 24 2012 [Corrected by Petros Hadjicostas, Aug 02 2020]
From Chai Wah Wu, Jan 28 2021: (Start)
a(n) = 5*a(n-1) - 4*a(n-2) for n > 3.
G.f.: x*(-2*x^2 - 2*x + 1)/((x - 1)*(4*x - 1)). (End)
MATHEMATICA
LinearRecurrence[{5, -4}, {0, 1, 3, 9}, 30] (* Harvey P. Dale, May 21 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 02 2003
STATUS
approved