a(n) = n^7 * Product_{p|n, p prime} (1 + 1/p^7).

Terms

a(0) =1a(1) =129a(2) =2188a(3) =16512a(4) =78126a(5) =282252a(6) =823544a(7) =2113536a(8) =4785156a(9) =10078254a(10) =19487172a(11) =36128256a(12) =62748518a(13) =106237176a(14) =170939688a(15) =270532608a(16) =410338674a(17) =617285124a(18) =893871740a(19) =1290016512a(20) =1801914272a(21) =2513845188a(22) =3404825448a(23) =4624416768a(24) =6103593750a(25) =8094558822a(26) =10465136172