p-INVERT of (1,1,1,1,1,...), where p(S) = (1 - S)^2 * (1 - 2*S).

Terms

a(0) =4a(1) =15a(2) =52a(3) =172a(4) =552a(5) =1736a(6) =5384a(7) =16536a(8) =50440a(9) =153112a(10) =463176a(11) =1397720a(12) =4210568a(13) =12668568a(14) =38083528a(15) =114414424a(16) =343587336a(17) =1031482904a(18) =3095956040a(19) =9291013848a(20) =27879595144a(21) =83652416920a(22) =250985562312a(23) =753015407192