Number of distinct solutions of sum{i=1..4}(x(2i-1)*x(2i)) = 0 (mod n), with x() in 0..n-1.

Terms

a(0) =1a(1) =9a(2) =45a(3) =205a(4) =620a(5) =1957a(6) =4507a(7) =11171a(8) =22146a(9) =45350a(10) =78661a(11) =151695a(12) =234757a(13) =405587a(14) =621513a(15) =995842a(16) =1396875a(17) =2214555a(18) =2949517a(19) =4476311a(20) =5932188a(21) =8399584a(22) =10743228a(23) =15648807a(24) =19058660a(25) =26160160a(26) =32743869a(27) =43862757a(28) =52161089a(29) =71513890