Partial sums of A066425.

Terms

a(0) =1a(1) =4a(2) =12a(3) =30a(4) =71a(5) =155a(6) =336a(7) =700a(8) =1451a(9) =2963a(10) =6000a(11) =12107a(12) =24323a(13) =48870a(14) =97987a(15) =196223a(16) =392767a(17) =785945a(18) =1572352a(19) =3145553a(20) =6291979a(21) =12584948a(22) =25171711a(23) =50345420a(24) =100693416a(25) =201390141a(26) =402783805a(27) =805571907a(28) =1611148335a(29) =3222301504