Triangle of tanh numbers.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =0a(5) =1a(6) =0a(7) =-2a(8) =0a(9) =1a(10) =0a(11) =0a(12) =-8a(13) =0a(14) =1a(15) =0a(16) =16a(17) =0a(18) =-20a(19) =0a(20) =1a(21) =0a(22) =0a(23) =136a(24) =0a(25) =-40a(26) =0a(27) =1a(28) =0a(29) =-272