a(n) = A059897(A260443(n), A260443(1+n)).

Terms

a(0) =2a(1) =6a(2) =2a(3) =30a(4) =90a(5) =270a(6) =2a(7) =210a(8) =630a(9) =6750a(10) =2250a(11) =378a(12) =15750a(13) =47250a(14) =2a(15) =2310a(16) =6930a(17) =6750a(18) =630a(19) =66150a(20) =198450a(21) =3402a(22) =90a(23) =14850a(24) =24750a(25) =92610a(26) =30870a(27) =14850a(28) =8489250a(29) =25467750