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!)
A086817 a(n) is the number of terms in the expansion of (x+y-z)*(x^2+y^2-z^2)*(x^3+y^3-z^3)*...*(x^n+y^n-z^n). 3

%I

%S 3,9,22,48,102,182,328,566,910,1396,2025,2882,3976,5304,7002,9071,

%T 11475,14444,17886,21896,26531,31880,37947,44899,52657,61500,71406,

%U 82383,94592,108097,123017,139401,157439,177134,198634,221962,247378,274767,304483,336533,371083,408168,447944,490614,536208

%N a(n) is the number of terms in the expansion of (x+y-z)*(x^2+y^2-z^2)*(x^3+y^3-z^3)*...*(x^n+y^n-z^n).

%p P:= 1;

%p for n from 1 to 90 do

%p P:= expand(P*(x^n+y^n-z^n));

%p A[n]:= nops(P);

%p od:

%p seq(A[n],n=1..90); # _Robert Israel_, Apr 14 2017

%t Table[Length[Expand[Times@@Table[x^n+y^n-z^n,{n,i}]]],{i,50}] (* _Harvey P. Dale_, Oct 02 2018 *)

%Y Cf. A086796.

%K nonn

%O 1,1

%A Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 06 2003

%E a(12)-a(45) from _Robert Israel_, Apr 14 2017

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 January 25 14:14 EST 2022. Contains 350572 sequences. (Running on oeis4.)