Sum at 45 degrees to horizontal in triangle of A081498.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =8a(5) =11a(6) =12a(7) =16a(8) =15a(9) =20a(10) =16a(11) =22a(12) =14a(13) =21a(14) =8a(15) =16a(16) =-3a(17) =6a(18) =-20a(19) =-10a(20) =-44a(21) =-33a(22) =-76a(23) =-64a(24) =-117a(25) =-104a(26) =-168a(27) =-154a(28) =-230a(29) =-215