Oblong numbers of the form 2^k*(2^k - 1) or 2^k*(2^k + 1).

Terms

a(0) =2a(1) =6a(2) =12a(3) =20a(4) =56a(5) =72a(6) =240a(7) =272a(8) =992a(9) =1056a(10) =4032a(11) =4160a(12) =16256a(13) =16512a(14) =65280a(15) =65792a(16) =261632a(17) =262656a(18) =1047552a(19) =1049600a(20) =4192256a(21) =4196352a(22) =16773120a(23) =16781312a(24) =67100672a(25) =67117056a(26) =268419072a(27) =268451840a(28) =1073709056a(29) =1073774592