A088271 Palindromic primes that yield a prime when sandwiched between two 7's. (Prefixing and suffixing a 'seven' on both sides yields another pal prime).

2, 5, 131, 191, 797, 11411, 15551, 30203, 31013, 32423, 36263, 36563, 38183, 39293, 72227, 74747, 77477, 94349, 94949, 1003001, 1055501, 1074701, 1085801, 1120211, 1123211, 1153511, 1178711, 1183811, 1221221, 1311131, 1317131, 1363631

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..100

Example

191 is a member as 71917 is also a prime.

Mathematica

Select[Prime[Range[110000]], PalindromeQ[#]&&PrimeQ[FromDigits[Join[{7}, IntegerDigits[#], {7}]]]&] (* Harvey P. Dale, Dec 19 2024 *)

Crossrefs

Cf. A088269, A088270, A088272.

Sequence in context: A093865 A139129 A139484 * A236045 A183128 A145620

Adjacent sequences: A088268 A088269 A088270 * A088272 A088273 A088274

Keyword

base,nonn

Author

Amarnath Murthy, Sep 28 2003

Extensions

More terms from David Wasserman, Jul 28 2005

Status

approved