login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 (list; graph; refs; listen; history; text; internal format)
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 A234097 A211562

Adjacent sequences:  A027980 A027981 A027982 * A027984 A027985 A027986

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 25 00:41 EDT 2017. Contains 288708 sequences.