Number of n-element subsets of [n+4] having an even sum.

Terms

a(0) =1a(1) =2a(2) =6a(3) =19a(4) =38a(5) =60a(6) =100a(7) =170a(8) =255a(9) =350a(10) =490a(11) =693a(12) =924a(13) =1176a(14) =1512a(15) =1956a(16) =2445a(17) =2970a(18) =3630a(19) =4455a(20) =5346a(21) =6292a(22) =7436a(23) =8814a(24) =10283a(25) =11830a(26) =13650a(27) =15785a(28) =18040a(29) =20400