Partial sums of A008534, or crystal ball sequence for {A_6}* lattice.

Terms

a(0) =1a(1) =15a(2) =113a(3) =575a(4) =2171a(5) =6581a(6) =16955a(7) =38613a(8) =79885a(9) =153091a(10) =275661a(11) =471395a(12) =771863a(13) =1217945a(14) =1861511a(15) =2767241a(16) =4014585a(17) =5699863a(18) =7938505a(19) =10867431a(20) =14647571a(21) =19466525a(22) =25541363a(23) =33121565a(24) =42492101a(25) =53976651