Number of nondecreasing integer sequences of length 10 with sum zero and sum of absolute values 2n.

Terms

a(0) =1a(1) =4a(2) =9a(3) =25a(4) =49a(5) =118a(6) =207a(7) =414a(8) =697a(9) =1240a(10) =1947a(11) =3299a(12) =4911a(13) =7690a(14) =11260a(15) =16787a(16) =23571a(17) =34111a(18) =46566a(19) =65168a(20) =87425a(21) =118613a(22) =155699a(23) =207823a(24) =267701a(25) =349081a(26) =444442a(27) =569884a(28) =714235a(29) =904372