An approximation to sigma_{5/2}(n): round( sum_{d|n} d^(5/2) ).

Terms

a(0) =1a(1) =7a(2) =17a(3) =39a(4) =57a(5) =110a(6) =131a(7) =220a(8) =260a(9) =379a(10) =402a(11) =641a(12) =610a(13) =870a(14) =944a(15) =1244a(16) =1193a(17) =1728a(18) =1575a(19) =2200a(20) =2167a(21) =2678a(22) =2538a(23) =3644a(24) =3182a(25) =4063a(26) =4048a(27) =5050a(28) =4530a(29) =6283