Half the number of length n integer sequences with sum zero and sum of squares 18.

A157535

Half the number of length n integer sequences with sum zero and sum of squares 18.

Terms

    a(0) =1a(1) =3a(2) =18a(3) =70a(4) =285a(5) =1533a(6) =7084a(7) =29604a(8) =116385a(9) =419815a(10) =1385142a(11) =4278066a(12) =12678757a(13) =36517950a(14) =102364200a(15) =278451568a(16) =733599079a(17) =1872496417a(18) =4639365470a(19) =11183927650a(20) =26287242751a(21) =60341512253a(22) =135432776524a(23) =297482865100

External references