Number of -1..1 arrays x(0..n+1) of n+2 elements with zero sum and nonzero second differences.

A200546

Number of -1..1 arrays x(0..n+1) of n+2 elements with zero sum and nonzero second differences.

Terms

    a(0) =4a(1) =14a(2) =26a(3) =72a(4) =142a(5) =362a(6) =778a(7) =1938a(8) =4366a(9) =10628a(10) =24532a(11) =59138a(12) =138680a(13) =333014a(14) =788374a(15) =1890870a(16) =4503208a(17) =10803262a(18) =25831504a(19) =62025512a(20) =148725902a(21) =357516682a(22) =859055042a(23) =2067463940a(24) =4975921904a(25) =11988835382a(26) =28892947100a(27) =69685951942

External references