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 11-14 of 14 results.

A032735 Palindromes that cannot be prefixed and followed by any digit to form a prime.

Original entry on oeis.org

11111, 60806, 65356, 1115111, 1392931, 1643461, 1762671, 1797971, 1799971, 1863681, 1911191, 2005002, 2190912, 2429242, 2499942, 2512152, 2708072, 2714172, 2794972, 2845482, 2848482, 2942492, 2993992, 3150513, 3239323
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Examples

			11111 prefixed and followed with a digit from (1,2,3,4,5,6,7,8,9) never yields a prime: '2'11111'3' = 29 x 72797.

Links

Crossrefs

Cf. A032682-A032685 and A032702-A032733.

A032688 Numbers k such that k surrounded by digit '5' is a lucky number.

Original entry on oeis.org

3, 23, 29, 32, 33, 38, 45, 51, 65, 75, 90, 96, 108, 110, 113, 116, 125, 132, 135, 147, 167, 183, 185, 186, 195, 204, 216, 218, 227, 236, 242, 246, 248, 254, 255, 257, 263, 275, 276, 278, 284, 293, 297, 300, 314, 315, 320, 323, 324, 326, 330, 338, 345, 347
Offset: 1

Views

Author

Patrick De Geest, May 15 1998

Keywords

Crossrefs

Cf. A000959, A032682.

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 11-14 of 14 results.

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

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