a(1) = 1; a(n) = Sum_{k=2..n} (-1)^k * k^2 * a(floor(n/k)).

Terms

a(0) =1a(1) =4a(2) =-5a(3) =23a(4) =-2a(5) =-29a(6) =-78a(7) =146a(8) =146a(9) =71a(10) =-50a(11) =-302a(12) =-471a(13) =-618a(14) =-393a(15) =1399a(16) =1110a(17) =1110a(18) =749a(19) =49a(20) =490a(21) =127a(22) =-402a(23) =-2418a(24) =-2418a(25) =-2925a(26) =-2925a(27) =-4297a(28) =-5138a(29) =-4463