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!)
A180785 Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 1..n-1 1

%I

%S 0,1,3,14,46,106,254,494,939,1528,2668,3958,6334,8641,13239,17240,

%T 25227,31128,44660,53786,74111,86712,118779,134632,181755,202431,

%U 266175,296323,387533,412008,544121,582432,736568,786710,1006750,1037604,1336781

%N Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 1..n-1

%C Column 3 of A180793

%H R. H. Hardin, <a href="/A180785/b180785.txt">Table of n, a(n) for n=1..444</a>

%e Solutions for sum of products of 3 1..3 pairs = 1 (mod 4) are

%e (1*1 + 1*1 + 1*3) (1*1 + 1*2 + 1*2) (1*1 + 1*2 + 2*3) (1*1 + 1*3 + 3*3)

%e (1*1 + 2*2 + 2*2) (1*1 + 2*3 + 2*3) (1*2 + 1*2 + 3*3) (1*2 + 1*3 + 2*2)

%e (1*2 + 2*3 + 3*3) (1*3 + 1*3 + 1*3) (1*3 + 2*2 + 2*3) (1*3 + 3*3 + 3*3)

%e (2*2 + 2*2 + 3*3) (2*3 + 2*3 + 3*3)

%K nonn

%O 1,3

%A _R. H. Hardin_ Sep 20 2010

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 August 19 06:22 EDT 2022. Contains 356216 sequences. (Running on oeis4.)