Number of solutions to +-1 +- 5 +- 12 +- ... +- n*(3*n-1)/2 = 0.

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =2a(7) =2a(8) =4a(9) =0a(10) =2a(11) =4a(12) =4a(13) =0a(14) =30a(15) =46a(16) =78a(17) =0a(18) =210a(19) =366a(20) =644a(21) =0a(22) =2032a(23) =3696a(24) =6694a(25) =0a(26) =21936a(27) =39886a(28) =73098a(29) =0