Number of arrays of -2..2 integers x(1..n) with every x(i) in a subsequence of length 1, 2, 3 or 4 with sum zero.
A193704
Number of arrays of -2..2 integers x(1..n) with every x(i) in a subsequence of length 1, 2, 3 or 4 with sum zero.
Terms
- a(0) =1a(1) =5a(2) =23a(3) =119a(4) =489a(5) =1987a(6) =8043a(7) =32599a(8) =132713a(9) =540913a(10) =2205225a(11) =8989861a(12) =36646831a(13) =149381195a(14) =608893037a(15) =2481878351a(16) =10116219555a(17) =41234080525a(18) =168071970545a(19) =685070063741
External references
- oeis: A193704