a(n) = Sum_{k >= 0} binomial(n,5*k+4).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =5a(6) =15a(7) =35a(8) =70a(9) =127a(10) =220a(11) =385a(12) =715a(13) =1430a(14) =3004a(15) =6385a(16) =13380a(17) =27370a(18) =54740a(19) =107883a(20) =211585a(21) =416405a(22) =826045a(23) =1652090a(24) =3321891a(25) =6690150a(26) =13455325a(27) =26985675a(28) =53971350a(29) =107746282