a(n) = sigma_7(n), the sum of the 7th powers of the divisors of n.

Terms

a(0) =1a(1) =129a(2) =2188a(3) =16513a(4) =78126a(5) =282252a(6) =823544a(7) =2113665a(8) =4785157a(9) =10078254a(10) =19487172a(11) =36130444a(12) =62748518a(13) =106237176a(14) =170939688a(15) =270549121a(16) =410338674a(17) =617285253a(18) =893871740a(19) =1290094638a(20) =1801914272a(21) =2513845188a(22) =3404825448a(23) =4624699020a(24) =6103593751a(25) =8094558822a(26) =10465138360