a(n) = floor(M(g(n-1)+1, ..., g(n))), where M = harmonic mean and g(n) = n^3 + n^2 + n + 1.

Terms

a(0) =2a(1) =8a(2) =26a(3) =60a(4) =117a(5) =203a(6) =324a(7) =487a(8) =696a(9) =958a(10) =1279a(11) =1666a(12) =2123a(13) =2657a(14) =3274a(15) =3981a(16) =4782a(17) =5684a(18) =6693a(19) =7816a(20) =9057a(21) =10423a(22) =11920a(23) =13555a(24) =15332a(25) =17258a(26) =19339a(27) =21582a(28) =23991a(29) =26573