a(n) = [x^n] 2 / (1 + x*(2*x + 3) + sqrt((x + 1)*(1 - 3*x))). Alternating row sums of A379907.

Terms

a(0) =1a(1) =-1a(2) =1a(3) =0a(4) =1a(5) =2a(6) =5a(7) =12a(8) =31a(9) =79a(10) =207a(11) =546a(12) =1457a(13) =3919a(14) =10621a(15) =28968a(16) =79459a(17) =219053a(18) =606611a(19) =1686660a(20) =4706879a(21) =13178956a(22) =37012219a(23) =104235300a(24) =294301801a(25) =832901237a(26) =2362328425a(27) =6713749632a(28) =19116443881a(29) =54526962682