OFFSET
1,1
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..3323
Robert Israel, Proof of conjectured formula
FORMULA
a(n) = A088040(n)^(1/4).
Apparently a(n) = 2^(n-2) - 1 for n>3.
Conjecture: a(n) = 3*a(n-1)-2*a(n-2) for n>5. G.f.: x*(4*x^4-2*x^2-3*x+2) / ((x-1)*(2*x-1)). [Colin Barker, Feb 05 2013]
Conjectures confirmed (see link). - Robert Israel, Aug 19 2019
MAPLE
2, 3, 3, seq(2^(n-2)-1, n=4...40); # Robert Israel, Aug 19 2019
MATHEMATICA
{2, 3, 3}~Join~Array[2^(# - 2) - 1 &, 30, 4] (* Michael De Vlieger, Aug 19 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 19 2003
EXTENSIONS
Corrected and extended by Ray Chandler, Oct 04 2003
STATUS
approved