A054658 Primes beginning 1, 3, 7, 9 whose reversals are nonprimes.

19, 103, 109, 127, 137, 139, 163, 173, 193, 197, 307, 317, 331, 349, 367, 379, 397, 719, 773, 911, 947, 977, 997, 1013, 1019, 1039, 1049, 1051, 1063, 1087, 1093, 1117, 1123, 1129, 1163, 1171, 1187, 1277, 1289, 1291, 1297, 1303, 1307, 1319, 1327, 1361

Offset: 1

Author

Enoch Haga, Apr 18 2000

Keywords

• easy
• nonn
• base

Comments

Or, primes whose reversals are composites ending in 1,3,7,9. - Lekraj Beedassy, Aug 02 2008

A subsequence of A143260. - Lekraj Beedassy, Aug 02 2008

Examples

			a(1)=19 because its reverse is a nonprime, 91.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A143260, A076056, A082768.

Programs

Mathematica

pbQ[p_]:=MemberQ[{1,3,7,9},IntegerDigits[p][[1]]]&&CompositeQ[IntegerReverse[p]]; Select[Prime[Range[300]],pbQ] (* Harvey P. Dale, Dec 02 2024 *)

Extensions

Edited by N. J. A. Sloane, Aug 29 2008 at the suggestion of R. J. Mathar