a(2*n) = A028230(n), a(2*n+1) = -A067900(n+1).

Terms

a(0) =1a(1) =-8a(2) =15a(3) =-112a(4) =209a(5) =-1560a(6) =2911a(7) =-21728a(8) =40545a(9) =-302632a(10) =564719a(11) =-4215120a(12) =7865521a(13) =-58709048a(14) =109552575a(15) =-817711552a(16) =1525870529a(17) =-11389252680a(18) =21252634831a(19) =-158631825968a(20) =296011017105