a(n) = A024955(n+3)/7.

Terms

a(0) =1a(1) =1a(2) =8a(3) =15a(4) =22a(5) =78a(6) =190a(7) =400a(8) =1051a(9) =2535a(10) =7456a(11) =18453a(12) =47188a(13) =126687a(14) =358191a(15) =954794a(16) =2455349a(17) =6649728a(18) =18661770a(19) =50325066a(20) =134032193a(21) =366103529a(22) =1031003534a(23) =2817678326a(24) =7634389540a(25) =20930031893a(26) =59436464774a(27) =163683320620a(28) =447761993141