Number of arrays of -3..3 integers x(1..n) with every x(i) in a subsequence of length 1, 2 or 3 with sum zero.
A193697
Number of arrays of -3..3 integers x(1..n) with every x(i) in a subsequence of length 1, 2 or 3 with sum zero.
Terms
- a(0) =1a(1) =7a(2) =43a(3) =181a(4) =827a(5) =3773a(6) =17197a(7) =78407a(8) =357403a(9) =1629369a(10) =7428007a(11) =33862711a(12) =154372795a(13) =703751937a(14) =3208252657a(15) =14625730979a(16) =66675552791a(17) =303959466209
External references
- oeis: A193697