login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A053459 Open disk numbers (version 4): a(n) is the number of points (i+j/2,j*sqrt(3)/2), i,j integers (triangular grid) contained in an open disk of diameter n, centered at (1/2,0). 3

%I #7 Mar 23 2022 12:51:03

%S 0,0,4,8,14,22,30,42,60,74,92,108,130,148,178,206,230,262,288,324,364,

%T 400,442,480,522,562,614,662,712,764,812,868,922,988,1050,1106,1176,

%U 1234,1312,1376,1452,1528,1598,1678,1750,1838,1920,2006,2092,2172,2266

%N Open disk numbers (version 4): a(n) is the number of points (i+j/2,j*sqrt(3)/2), i,j integers (triangular grid) contained in an open disk of diameter n, centered at (1/2,0).

%C a(n)/(n/2)^2 -> Pi*2/sqrt(3).

%Y Cf. A053417, A053456, A053457, A053458.

%K easy,nonn

%O 0,3

%A Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 13 2000

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 00:26 EDT 2024. Contains 371264 sequences. (Running on oeis4.)