login
A027983
T(n,n+1) + T(n,n+2) + ... + T(n,2n), T given by A027960.
1
1, 5, 14, 35, 81, 180, 389, 825, 1726, 3575, 7349, 15020, 30561, 61965, 125294, 252795, 509161, 1024100, 2057549, 4130225, 8284926, 16609455, 33282989, 66669660, 133507081, 267285605, 535010414, 1070731475, 2142612801
OFFSET
0,2
COMMENTS
Is this the same as A027974? - R. J. Mathar, Oct 23 2008
FORMULA
Conjectured formula: a(n) = 2 * a(n - 1) + L(n + 1), where L(m) is the m-th Lucas number, as in A000032. - David A. Corneth, Apr 16 2015
Conjectures from Colin Barker, Feb 17 2016: (Start)
a(n) = 2^(-1-n)*(4^(2+n)+(1-sqrt(5))^n*(-7+3*sqrt(5))-(1+sqrt(5))^n*(7+3*sqrt(5))).
a(n) = 3*a(n-1)-a(n-2)-2*a(n-3) for n>2.
G.f.: (1+2*x) / ((1-2*x)*(1-x-x^2)).
(End)
CROSSREFS
Sequence in context: A066767 A227200 A027974 * A142585 A332743 A234097
KEYWORD
nonn
STATUS
approved