Numbers n such that 3*T(n)+1 is a square, where T = A000217.

Terms

a(0) =0a(1) =1a(2) =6a(3) =15a(4) =64a(5) =153a(6) =638a(7) =1519a(8) =6320a(9) =15041a(10) =62566a(11) =148895a(12) =619344a(13) =1473913a(14) =6130878a(15) =14590239a(16) =60689440a(17) =144428481a(18) =600763526a(19) =1429694575a(20) =5946945824a(21) =14152517273a(22) =58868694718a(23) =140095478159a(24) =582740001360