Number of distinct solutions of sum{i=1..7}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2.

A180819

Number of distinct solutions of sum{i=1..7}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =9a(5) =168a(6) =1636a(7) =16029a(8) =98932a(9) =566139a(10) =2452576a(11) =9997696a(12) =33559251a(13) =107928162a(14) =302208130a(15) =819882076a(16) =1997861697a(17) =4777963921a(18) =10461759204a(19) =22651681426a(20) =45635928642a(21) =91229866983a(22) =171539771236a(23) =322071749769

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