A068893 Nonpalindromic numbers that have the same prime signature as their digit reversal.

13, 15, 17, 26, 31, 37, 39, 51, 58, 62, 71, 73, 79, 85, 93, 97, 107, 113, 115, 117, 122, 123, 129, 143, 149, 155, 157, 158, 159, 165, 167, 169, 177, 178, 179, 183, 185, 187, 199, 203, 205, 221, 226, 246, 265, 285, 286, 294, 302, 311, 314, 319, 321, 326, 327

Offset: 1

Author

Amarnath Murthy, Mar 20 2002

Keywords

• base
• easy
• nonn

Examples

			15 is a term since 15 = 3*5 and 51 = 3*17, and both are of the form p*q where p and q are primes.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to prime signature

Crossrefs

Subsequence of A085869.

Cf. A004086, A118914.

Programs

Mathematica

sig[n_] := Sort @ FactorInteger[n][[;;,2]]; Select[Range[300], !PalindromeQ[#] && sig[#] == sig[IntegerReverse[#]] &] (* Amiram Eldar, Dec 30 2020 *)

Extensions

More terms from David Wasserman, Apr 19 2005

Offset corrected by Amiram Eldar, Dec 30 2020