a(n) = ceiling((n+1/n)^4).

Terms

a(0) =16a(1) =40a(2) =124a(3) =327a(4) =732a(5) =1447a(6) =2604a(7) =4359a(8) =6892a(9) =10407a(10) =15132a(11) =21319a(12) =29244a(13) =39207a(14) =51532a(15) =66567a(16) =84684a(17) =106279a(18) =131772a(19) =161607a(20) =196252a(21) =236199a(22) =281964a(23) =334087a(24) =393132a(25) =459687a(26) =534364a(27) =617799a(28) =710652a(29) =813607