a(n) = n^7 * Sum_{d^2|n} 1 / d^7.

Terms

a(0) =1a(1) =128a(2) =2187a(3) =16512a(4) =78125a(5) =279936a(6) =823543a(7) =2113536a(8) =4785156a(9) =10000000a(10) =19487171a(11) =36111744a(12) =62748517a(13) =105413504a(14) =170859375a(15) =270548992a(16) =410338673a(17) =612499968a(18) =893871739a(19) =1290000000a(20) =1801088541a(21) =2494357888a(22) =3404825447a(23) =4622303232a(24) =6103593750a(25) =8031810176a(26) =10465136172