a(n) = smallest m such that A031131(m) = 2*n.

Terms

a(0) =2a(1) =3a(2) =9a(3) =8a(4) =15a(5) =23a(6) =47a(7) =29a(8) =66a(9) =114a(10) =46a(11) =220a(12) =188a(13) =258a(14) =640a(15) =375a(16) =480a(17) =589a(18) =216a(19) =326a(20) =367a(21) =1006a(22) =738a(23) =1183a(24) =1985a(25) =1847a(26) =1662a(27) =2224a(28) =3731a(29) =3861