a(1)=1, a(n)=a(n-1)+n^1 if n odd, a(n)=a(n-1)+ n^4 if n is even.

Terms

a(0) =1a(1) =17a(2) =20a(3) =276a(4) =281a(5) =1577a(6) =1584a(7) =5680a(8) =5689a(9) =15689a(10) =15700a(11) =36436a(12) =36449a(13) =74865a(14) =74880a(15) =140416a(16) =140433a(17) =245409a(18) =245428a(19) =405428a(20) =405449a(21) =639705a(22) =639728a(23) =971504a(24) =971529a(25) =1428505a(26) =1428532a(27) =2043188a(28) =2043217a(29) =2853217