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.

Previous Showing 21-27 of 27 results.

A032709 Numbers k such that k prefixed by '9' and followed by '1' is prime.

Original entry on oeis.org

1, 4, 7, 9, 15, 16, 18, 22, 24, 28, 31, 34, 37, 39, 42, 43, 46, 49, 51, 52, 55, 60, 63, 66, 72, 78, 79, 81, 85, 87, 90, 93, 94, 108, 112, 114, 115, 129, 133, 138, 141, 154, 157, 159, 162, 163, 169, 171, 177, 178, 180, 181, 184, 192, 195, 196, 204, 205, 211, 222
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Crossrefs

Cf. A032702-A032733.

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024

A032712 Numbers k such that k prefixed by '4' and followed by '3' is prime.

Original entry on oeis.org

3, 4, 6, 13, 15, 24, 25, 27, 28, 36, 37, 42, 46, 48, 49, 51, 52, 58, 60, 64, 66, 67, 70, 72, 73, 78, 79, 81, 90, 93, 94, 97, 99, 102, 111, 114, 118, 120, 121, 123, 124, 126, 133, 141, 144, 145, 151, 154, 159, 160, 181, 184, 186, 189, 190, 195, 198, 201, 202
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Crossrefs

Cf. A032702-A032733.

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024

A032718 Numbers k such that k prefixed by '1' and followed by '7' is prime.

Original entry on oeis.org

0, 2, 3, 5, 6, 9, 11, 18, 21, 23, 27, 29, 30, 32, 36, 42, 44, 48, 56, 59, 60, 62, 63, 65, 66, 69, 74, 77, 78, 84, 86, 87, 90, 98, 99, 102, 104, 105, 108, 111, 117, 119, 125, 128, 131, 143, 144, 146, 149, 152, 158, 159, 161, 165, 167, 171, 177, 180, 182, 186
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Crossrefs

Cf. A032702-A032733.

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024

A032722 Numbers k such that k prefixed by '5' and followed by '7' is prime.

Original entry on oeis.org

4, 5, 7, 8, 10, 14, 16, 19, 22, 23, 29, 34, 38, 40, 41, 43, 47, 50, 52, 55, 64, 65, 71, 73, 80, 82, 85, 86, 89, 92, 98, 104, 113, 115, 119, 121, 125, 128, 130, 134, 140, 142, 143, 148, 151, 157, 160, 163, 164, 176, 178, 179, 181, 182, 190, 197, 202, 205, 206, 212
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Crossrefs

Cf. A032702-A032733.

Programs

  • Mathematica
    Select[Range[250],PrimeQ[FromDigits[Join[{5},IntegerDigits[#], {7}]]]&] (* Harvey P. Dale, Jul 24 2011 *)

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024

A032730 Numbers k such that k prefixed by '5' and followed by '9' is prime.

Original entry on oeis.org

0, 6, 9, 11, 17, 18, 20, 27, 30, 39, 41, 44, 47, 51, 56, 63, 65, 66, 68, 74, 77, 83, 84, 86, 87, 93, 105, 110, 116, 119, 122, 123, 132, 134, 141, 143, 144, 147, 153, 159, 165, 167, 171, 174, 176, 182, 183, 185, 186, 189, 192, 194, 200, 206, 218, 224, 225
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Crossrefs

Cf. A032702-A032733.

Programs

  • Mathematica
    Select[Range[0,250],PrimeQ[FromDigits[Join[{5},IntegerDigits[#], {9}]]]&] (* Harvey P. Dale, May 09 2011 *)

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024

A032736 a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes allowed).

Original entry on oeis.org

14612, 27971, 29289, 33170, 36186, 38327, 39608, 40078, 41165, 41528, 43277, 44657, 47382, 55553, 55791, 58899, 60806, 62318, 63056, 65970, 66818, 70558, 73851, 80477, 81167, 83986, 86145, 89072, 89280, 90379, 91538, 93160, 96222
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Examples

			60806 prefixed with a digit from ('',1,2,3,4,5,6,7,8,9) and followed by a digit from (1,3,7,9) never yields a prime: '_'60806'3' = 43 x 79 x 179; '1'14612'3' = 3^3 x 11 x 17 x 227.

Crossrefs

Cf. A032682-A032685 and A032702-A032733.

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024

A032738 a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes and suffixes are allowed).

Original entry on oeis.org

14612, 27971, 33170, 36186, 39608, 40078, 41165, 41528, 47382, 55553, 60806, 62318, 63056, 65970, 66818, 70558, 83986, 86145, 89072, 89280, 91538, 93160, 96222, 97908, 101532, 102852, 104609, 105275, 108312, 108615, 108792, 109934
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Comments

a(n) itself cannot be a prime to start with.

Examples

			104609 prefixed or followed by a digit from ('',1,2,3,4,5,6,7,8,9) never yields a prime: '_'104609'_' = 73 x 1433; '8'104609'3' = 3089 x 26237.

Crossrefs

Cf. A032682-A032685 and A032702-A032733.

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024
Previous Showing 21-27 of 27 results.

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

Content is available under The OEIS End-User License Agreement.