A176556 Nonprime concatenations of divisors of some k, ordered by k.

1, 12, 124, 15, 1236, 1248, 12510, 111, 1234612, 12714, 13515, 124816, 117, 1236918, 119, 12451020, 121122, 123, 1234681224, 1525, 121326, 13927, 12471428, 129, 12356101530, 12481632, 131133, 121734, 15735, 123469121836, 121938, 131339

Offset: 1

Author

Jaroslav Krizek, Apr 20 2010

Keywords

• nonn
• base

Comments

Intersection of A037278 and A018252.

Examples

			For n = 6; a(6) = 1248 because A176554(6) = 8 and divisors of 8 are 1, 2, 4, 8; concatenation of divisors A037278(8) = 1248 is nonprime number.
		

Formula

a(n) = A037278(A176554(n)).

Extensions

Extended and edited by Charles R Greathouse IV, Apr 27 2010