OFFSET
0,3
LINKS
Christopher Bao, Yunseo Choi, Katelyn Gan, and Owen Zhang, On a Conjecture by Baril, Cerbai, Khalil, and Vajnovszki on Two Restricted Stacks, arXiv:2308.09344 [math.CO], 2023. See Theorems 1.1 and 1.2, pp. 2-3.
Index entries for linear recurrences with constant coefficients, signature (2).
FORMULA
a(0) = 1, a(n) = 2^(n-1) for n = 1..3, a(n) = 7*2^(n-4) for n > 3.
From Chai Wah Wu, Aug 24 2023: (Start)
a(n) = 2*a(n-1) for n > 4.
G.f.: (x^4 + x - 1)/(2*x - 1). (End)
MATHEMATICA
{1}~Join~Array[If[# <= 3, 2^(# - 1), 7*2^(# - 4)] &, 30]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Michael De Vlieger, Aug 23 2023
STATUS
approved