a(1) = 1, a(2) = 1, a(n) = sum of tau(n) previous terms, where tau(n) is the number of divisors of n.

A087549

a(1) = 1, a(2) = 1, a(n) = sum of tau(n) previous terms, where tau(n) is the number of divisors of n.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =6a(5) =13a(6) =19a(7) =42a(8) =74a(9) =148a(10) =222a(11) =518a(12) =740a(13) =1628a(14) =3108a(15) =6216a(16) =9324a(17) =21534a(18) =30858a(19) =72668a(20) =134384a(21) =259444a(22) =393828a(23) =928256a(24) =1581528a(25) =3163056a(26) =6066668a(27) =12392780a(28) =18459448a(29) =43245008

External references