a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = floor(n/2), s = (odd natural numbers).

Terms

a(0) =3a(1) =5a(2) =22a(3) =30a(4) =73a(5) =91a(6) =172a(7) =204a(8) =335a(9) =385a(10) =578a(11) =650a(12) =917a(13) =1015a(14) =1368a(15) =1496a(16) =1947a(17) =2109a(18) =2670a(19) =2870a(20) =3553a(21) =3795a(22) =4612a(23) =4900a(24) =5863a(25) =6201a(26) =7322a(27) =7714a(28) =9005a(29) =9455