Number of solutions to 1^3*k_1 + 2^3*k_2 + ... + n^3*k_n = 1, where k_i are from {-1,0,1}, i=1..n.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =3a(7) =4a(8) =6a(9) =15a(10) =28a(11) =56a(12) =125a(13) =287a(14) =646a(15) =1540a(16) =3625a(17) =8484a(18) =21167a(19) =51458a(20) =126342a(21) =323126a(22) =811538a(23) =2052501a(24) =5339265a(25) =13751212a(26) =35589866a(27) =94032931a(28) =246791641a(29) =650227636