login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A203902 a(n)=f(a(n-1)+1,a(n-2)+1,a(n-3)+1), where f(x,y,z)=yz+zx+xy and (a(1),a(2),a(3))=(0,0,1). 2

%I

%S 0,0,1,5,20,180,5013,1016629,5282300384,5396635591915760,

%T 28512136651893281578375965,

%U 153869762066843605647265362776201153415021,4387155683474529138873327728747664927423052537019723373711103123120

%N a(n)=f(a(n-1)+1,a(n-2)+1,a(n-3)+1), where f(x,y,z)=yz+zx+xy and (a(1),a(2),a(3))=(0,0,1).

%C For a guide to related sequences, see A203761.

%t a[1] = 0; a[2] = 0; a[3] = 1;

%t a[n_] := SymmetricPolynomial[2, {1 + a[n - 1], 1 + a[n - 2], 1 + a[n - 3]}]

%t Table[a[n], {n, 1, 13}] (* A203902 *)

%Y Cf. A203761.

%K nonn

%O 1,4

%A _Clark Kimberling_, Jan 07 2012

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 26 21:33 EDT 2021. Contains 348269 sequences. (Running on oeis4.)