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!)
A180826 Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 2..n-2 1
0, 0, 0, 0, 2, 5, 30, 69, 197, 311, 772, 1108, 2260, 2939, 5428, 6860, 11681, 13562, 22572, 25991, 39771, 44766, 68086, 73210, 109117, 116321, 164828, 177996, 250708, 252738, 362504, 373956, 499036, 517654, 703195, 693797, 953734, 950028, 1235597 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
COMMENTS
Column 3 of A180834
LINKS
EXAMPLE
Solutions for sum of products of 3 2..5 pairs = 1 (mod 7) are
(2*2 + 2*3 + 3*4) (2*2 + 2*4 + 2*5) (2*2 + 2*5 + 3*5) (2*2 + 3*3 + 3*3)
(2*2 + 3*3 + 4*4) (2*2 + 3*4 + 4*5) (2*2 + 4*4 + 4*4) (2*3 + 2*3 + 2*5)
(2*3 + 2*4 + 2*4) (2*3 + 2*4 + 3*5) (2*3 + 2*5 + 4*5) (2*3 + 3*4 + 5*5)
(2*3 + 3*5 + 3*5) (2*4 + 2*4 + 4*5) (2*4 + 2*5 + 5*5) (2*4 + 3*3 + 3*4)
(2*4 + 3*4 + 4*4) (2*4 + 3*5 + 4*5) (2*5 + 2*5 + 3*3) (2*5 + 2*5 + 4*4)
(2*5 + 3*5 + 5*5) (2*5 + 4*5 + 4*5) (3*3 + 3*3 + 5*5) (3*3 + 3*4 + 3*5)
(3*3 + 4*4 + 5*5) (3*4 + 3*4 + 3*4) (3*4 + 3*5 + 4*4) (3*4 + 4*5 + 5*5)
(3*5 + 3*5 + 4*5) (4*4 + 4*4 + 5*5)
CROSSREFS
Sequence in context: A109739 A261414 A163800 * A367521 A209325 A019027
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 20 2010
STATUS
approved

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 08:53 EDT 2024. Contains 371268 sequences. (Running on oeis4.)