a(n) = Sum_{k=1..n} k^2*phi(k), where phi is the Euler totient function A000010.

Terms

a(0) =1a(1) =5a(2) =23a(3) =55a(4) =155a(5) =227a(6) =521a(7) =777a(8) =1263a(9) =1663a(10) =2873a(11) =3449a(12) =5477a(13) =6653a(14) =8453a(15) =10501a(16) =15125a(17) =17069a(18) =23567a(19) =26767a(20) =32059a(21) =36899a(22) =48537a(23) =53145a(24) =65645a(25) =73757a(26) =86879a(27) =96287a(28) =119835a(29) =127035