a(n) = A154570(n) + A154570(n+1).

Terms

a(0) =4a(1) =-1a(2) =-2a(3) =-4a(4) =-8a(5) =-16a(6) =-32a(7) =-64a(8) =-128a(9) =-256a(10) =-512a(11) =-1024a(12) =-2048a(13) =-4096a(14) =-8192a(15) =-16384a(16) =-32768a(17) =-65536a(18) =-131072a(19) =-262144a(20) =-524288a(21) =-1048576a(22) =-2097152a(23) =-4194304a(24) =-8388608a(25) =-16777216a(26) =-33554432a(27) =-67108864a(28) =-134217728a(29) =-268435456