Number of solutions to 1 +-* 2 +-* 3 +-* ... +-* n = 0.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =1a(5) =4a(6) =6a(7) =14a(8) =29a(9) =63a(10) =129a(11) =300a(12) =756a(13) =1677a(14) =4134a(15) =9525a(16) =22841a(17) =57175a(18) =141819a(19) =354992a(20) =882420a(21) =2218078a(22) =5588989a(23) =14173217a(24) =35918542