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

1,1

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

Links

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

Example

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

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 *)

Crossrefs

Cf. A143260, A076056, A082768.

Sequence in context: A245528 A253218 A300774 * A023296 A139948 A101010

Adjacent sequences: A054655 A054656 A054657 * A054659 A054660 A054661

Keyword

easy,nonn,base

Author

Enoch Haga, Apr 18 2000

Extensions

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

Status

approved