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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A007904 Crystal ball sequence for diamond. 2
1, 5, 17, 41, 83, 147, 239, 363, 525, 729, 981, 1285, 1647, 2071, 2563, 3127, 3769, 4493, 5305, 6209, 7211, 8315, 9527, 10851, 12293, 13857, 15549, 17373, 19335, 21439, 23691, 26095, 28657, 31381, 34273, 37337 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Equals binomial transform of [1, 4, 8, 4, 2, -4, 8, -16, 32, -64, 128,...] [From Gary W. Adamson, Feb 07 2010]

LINKS

T. D. Noe, Table of n, a(n) for n = 0..1000

Index entries for crystal ball sequences

J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (pdf).

MAPLE

G.f.: -(x^4+2*x^3+4*x^2+2*x+1)/(x-1)^2/(x^2-1)/(1-x).

MATHEMATICA

b[0]=1; b[1]=4; b[2]=8; b[3]=4; b[n_] := (-1)^n*2^(n-3); a[n_] := Sum[Binomial[n, k]*b[k], {k, 0, n}]; Table[a[n], {n, 0, 35}] (* Jean-Fran├žois Alcover, Aug 08 2012, after Gary W. Adamson *)

CROSSREFS

Sequence in context: A304079 A109722 A097121 * A139545 A106972 A086499

Adjacent sequences:  A007901 A007902 A007903 * A007905 A007906 A007907

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane.

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 November 16 03:09 EST 2018. Contains 317252 sequences. (Running on oeis4.)