A027983 T(n,n+1) + T(n,n+2) + ... + T(n,2n), T given by A027960.

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

Links

Table of n, a(n) for n=0..28.

Philipp Emanuel Weidmann, The Sequencer OEIS Survey

Susanne Wienand, Suggestion for a proof of Philipp Emanuel Weidman's conjecture concerning A027983

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

Adjacent sequences: A027980 A027981 A027982 * A027984 A027985 A027986

Keyword

nonn

Author

Clark Kimberling

Status

approved