A176588 a(n) = A176558(A175354(n)) = numbers m as reverse concatenations of divisors of numbers from A175354, where A175354 = numbers k such that reverse concatenations of divisors of k are nonprimes.

1, 21, 51, 6321, 8421, 931, 10521, 111, 1264321, 14721, 15531, 168421, 171, 1896321, 20105421, 21731, 221121, 231, 2412864321, 261321, 27931, 28147421, 291, 30151065321, 32168421, 331131, 341721, 35751, 361812964321, 371

Offset: 1

Author

Jaroslav Krizek, Apr 21 2010

Keywords

• nonn
• base

Examples

			a(9) = 1264321 because A089374(9) = 12 and divisors of 12 are 1, 2, 3, 4, 6, 12; reverse concatenation of divisors A176558(12) = 1264321 is nonprime.
		

Crossrefs

Subsequence of A176558(n) = reverse concatenation of divisors of n.

Extensions

Edited by Charles R Greathouse IV, Apr 24 2010