a(n) is the smallest number k for which k and the arithmetic derivative k' (A003415) have exactly n triangular divisors (A000217).

A357842

a(n) is the smallest number k for which k and the arithmetic derivative k' (A003415) have exactly n triangular divisors (A000217).

Terms

    a(0) =2a(1) =27a(2) =18a(3) =72a(4) =612a(5) =1764a(6) =756a(7) =8100a(8) =27000a(9) =97200a(10) =66528a(11) =175500a(12) =93600a(13) =280800a(14) =1731600a(15) =661500a(16) =680400a(17) =3704400a(18) =34177500a(19) =11107800a(20) =16581600a(21) =20065500a(22) =108486000a(23) =102910500a(24) =108353700a(25) =181912500a(26) =314874000a(27) =462672000a(28) =4408236000a(29) =229975200

External references