Deleham triangle [1,1,-1,1,1,-1,1,...] DELTA [1,0,0,1,0,0,1,0,...], DELTA defined in A084938.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =1a(6) =3a(7) =7a(8) =5a(9) =1a(10) =4a(11) =13a(12) =15a(13) =7a(14) =1a(15) =4a(16) =19a(17) =33a(18) =26a(19) =9a(20) =1a(21) =2a(22) =19a(23) =53a(24) =66a(25) =40a(26) =11a(27) =1a(28) =-3a(29) =3