a(n) = (n+1)*2^n - n.

Terms

a(0) =1a(1) =3a(2) =10a(3) =29a(4) =76a(5) =187a(6) =442a(7) =1017a(8) =2296a(9) =5111a(10) =11254a(11) =24565a(12) =53236a(13) =114675a(14) =245746a(15) =524273a(16) =1114096a(17) =2359279a(18) =4980718a(19) =10485741a(20) =22020076a(21) =46137323a(22) =96468970a(23) =201326569a(24) =419430376a(25) =872415207a(26) =1811939302a(27) =3758096357a(28) =7784628196a(29) =16106127331