a(1) = 1; a(n) = gcd {n*(n+1), a(n-1) * (a(n-1) + 1)} for n > 1.

Terms

a(0) =1a(1) =2a(2) =6a(3) =2a(4) =6a(5) =42a(6) =14a(7) =6a(8) =6a(9) =2a(10) =6a(11) =6a(12) =14a(13) =210a(14) =30a(15) =2a(16) =6a(17) =6a(18) =2a(19) =6a(20) =42a(21) =2a(22) =6a(23) =6a(24) =2a(25) =6a(26) =42a(27) =14a(28) =30a(29) =930