cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A103993 Duplicate of A088269.

Original entry on oeis.org

3, 5, 131, 383, 797, 11411, 16061, 16361, 19391, 33533, 36263, 73037, 75557, 79397
Offset: 1

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Author

Keywords

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).

Original entry on oeis.org

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

Views

Author

Amarnath Murthy, Sep 28 2003

Keywords

Examples

			191 is a member as 71917 is also a prime.

Links

Crossrefs

Cf. A088269, A088270, A088272.

Programs

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

Extensions

More terms from David Wasserman, Jul 28 2005

A088270 Palindromic primes that yield a prime when sandwiched between two 3's. (Prefixing and suffixing a -three' on both sides yields another pal prime).

Original entry on oeis.org

5, 7, 101, 151, 353, 727, 757, 929, 10301, 10601, 12721, 15551, 16061, 16661, 18181, 19391, 19891, 30403, 30703, 31013, 31513, 35353, 36263, 36563, 38083, 39293, 72227, 73237, 76367, 77377, 77477, 78487, 79397, 79997, 93139, 94649, 94849
Offset: 1

Views

Author

Amarnath Murthy, Sep 28 2003

Keywords

Examples

			757 is a member as 37573 is also a prime.

Crossrefs

Cf. A088269, A088271, A088272.

Programs

  • Mathematica
    s23Q[n_]:=Module[{idn=IntegerDigits[n]},idn==Reverse[idn]&&PrimeQ[ FromDigits[Join[{3},idn,{3}]]]]; Select[Prime[Range[10000]],s23Q] (* Harvey P. Dale, May 07 2011 *)

Extensions

More terms from David Wasserman, Jul 28 2005

A088272 Palindromic primes that yield a prime when sandwiched between two 9's.

Original entry on oeis.org

2, 101, 313, 373, 757, 787, 10301, 12721, 12821, 17471, 17971, 19991, 32423, 35153, 35753, 37573, 72727, 73237, 77977, 78787, 78887, 90709, 93139, 93239, 97879, 1035301, 1117111, 1120211, 1129211, 1134311, 1178711, 1183811, 1186811
Offset: 1

Views

Author

Amarnath Murthy, Sep 28 2003

Keywords

Examples

			373 is a member as 93739 is also a prime.

Crossrefs

Cf. A088269, A088270, A088271.

Extensions

More terms from David Wasserman, Jul 28 2005
Showing 1-4 of 4 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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