a(n) = binomial(n, floor(n/6)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =6a(7) =7a(8) =8a(9) =9a(10) =10a(11) =11a(12) =66a(13) =78a(14) =91a(15) =105a(16) =120a(17) =136a(18) =816a(19) =969a(20) =1140a(21) =1330a(22) =1540a(23) =1771a(24) =10626a(25) =12650a(26) =14950a(27) =17550a(28) =20475a(29) =23751