Number of arrays of -5..5 integers x(1..n) with every x(i) in a subsequence of length 1 or 2 with sum zero.

A193645

Number of arrays of -5..5 integers x(1..n) with every x(i) in a subsequence of length 1 or 2 with sum zero.

Terms

    a(0) =1a(1) =11a(2) =31a(3) =151a(4) =561a(5) =2361a(6) =9361a(7) =38171a(8) =153591a(9) =621911a(10) =2510721a(11) =10150321a(12) =41008321a(13) =165729931a(14) =669676751a(15) =2706201271a(16) =10935546481a(17) =44190379881a(18) =178571332881a(19) =721601251291

External references