Number of n-element subsets of [n+6] having an even sum.

Terms

a(0) =1a(1) =3a(2) =12a(3) =44a(4) =110a(5) =226a(6) =452a(7) =868a(8) =1519a(9) =2485a(10) =3976a(11) =6216a(12) =9324a(13) =13524a(14) =19320a(15) =27192a(16) =37389a(17) =50391a(18) =67188a(19) =88660a(20) =115258a(21) =147862a(22) =188188a(23) =237692a(24) =297115a(25) =367913a(26) =452816a(27) =554064a(28) =672792a(29) =811240