The main diagonal of the successive differences of A154127.

Terms

a(0) =1a(1) =3a(2) =-4a(3) =2a(4) =-6a(5) =-2a(6) =-14a(7) =-18a(8) =-46a(9) =-82a(10) =-174a(11) =-338a(12) =-686a(13) =-1362a(14) =-2734a(15) =-5458a(16) =-10926a(17) =-21842a(18) =-43694a(19) =-87378a(20) =-174766a(21) =-349522a(22) =-699054a(23) =-1398098a(24) =-2796206a(25) =-5592402a(26) =-11184814a(27) =-22369618a(28) =-44739246a(29) =-89478482