Number of solutions to +-1 +- 3 +- 6 +- 10 +- ... +- n*(n + 1)/2 = n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =0a(4) =0a(5) =1a(6) =3a(7) =0a(8) =4a(9) =3a(10) =9a(11) =0a(12) =27a(13) =43a(14) =71a(15) =0a(16) =190a(17) =318a(18) =604a(19) =0a(20) =1846a(21) =3127a(22) =5664a(23) =0a(24) =19048a(25) =34065a(26) =62045a(27) =0a(28) =205713a(29) =378243