This site is supported by donations to The OEIS Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A274973 Centered cubohemioctahedral numbers: a(n) = 2*n^3+9*n^2+n+1. 2

%I

%S 1,13,55,139,277,481,763,1135,1609,2197,2911,3763,4765,5929,7267,8791,

%T 10513,12445,14599,16987,19621,22513,25675,29119,32857,36901,41263,

%U 45955,50989,56377,62131,68263,74785,81709,89047,96811,105013,113665,122779,132367

%N Centered cubohemioctahedral numbers: a(n) = 2*n^3+9*n^2+n+1.

%C A faceting of the cuboctahedron, sharing the same square faces. The cubohemioctahedron has the same edge and vertex arrangement as the cuboctahedron. Beginning with the fourth term, the eight tetrahedral faces are each now "missing" a tetrahedron of size 1,4,10,20,35...(A000292). See A274974 centered octahemioctahedron for similar cuboctahedral faceting but with the square faces "missing."

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Cubohemioctahedron">Cubohemioctahedron</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).

%F a(n) = 2*n^3+9*n^2+n+1.

%F G.f.: (-7*x^3+9*x^2+9*x+1)/(x-1)^4.

%t Table[2 n^3 + 9 n^2 + n + 1, {n, 40}] (* _Michael De Vlieger_, Jul 13 2016 *)

%o (PARI) a(n)=2*n^3+9*n^2+n+1 \\ _Charles R Greathouse IV_, Jul 14 2016

%Y Cf. A005902 (centered cuboctahedral numbers), A274974 (centered octahemioctahedral numbers).

%K nonn,easy

%O 0,2

%A _Steven Beard_, Jul 13 2016

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

Last modified January 20 16:46 EST 2019. Contains 319335 sequences. (Running on oeis4.)