a(n) = Sum_{k>=0} binomial(n,5*k+2).

Terms

a(0) =0a(1) =0a(2) =1a(3) =3a(4) =6a(5) =10a(6) =15a(7) =22a(8) =36a(9) =72a(10) =165a(11) =385a(12) =859a(13) =1807a(14) =3614a(15) =6995a(16) =13380a(17) =25773a(18) =50559a(19) =101118a(20) =204820a(21) =416405a(22) =843756a(23) =1698458a(24) =3396916a(25) =6765175a(26) =13455325a(27) =26789257a(28) =53457121a(29) =106914242