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.

A084987 Duplicate of A083185.

Original entry on oeis.org

11, 101, 181, 191, 919, 10601, 11411, 16061, 16661, 18181, 18481, 19891, 19991
Offset: 1

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Author

Keywords

A174884 Palindromic primes using only (decimal) square digits 0,1,4,9.

Original entry on oeis.org

11, 101, 191, 919, 11411, 19991, 91019, 94049, 94949, 1114111, 1190911, 1409041, 1411141, 1444441, 1490941, 1909091, 1941491, 9049409, 9091909, 9109019, 9110119, 9149419, 9199919, 9400049, 9414149, 9419149, 9440449, 9919199
Offset: 1

Views

Author

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Apr 01 2010

Keywords

Comments

Four decimal square digits: 0 = 0^2, 1 = 1^2, 4 = 2^2, 9 = 3^2
With the exception of 11 all palindromic primes have an odd number of digits

Examples

			11 = prime(5) = palprime(5), 1st term of sequence.
101 = prime(26) = palprime(6), 2nd term of sequence.
Next term using only 0 and 1 is 100111001 = prime(5767473) = palprime(785).

References

  • Roland Sprague, Unterhaltsame Mathematik, neue Probleme, ueberraschende Loesungen, Vieweg, Braunschweig, 1961
  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Books: London, 1986.

Links

Crossrefs

Cf. A002385, A007500, A083185, A155214.

Programs

  • Mathematica
    Select[FromDigits/@Tuples[{0,1,4,9},7],PalindromeQ[#]&&PrimeQ[#]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 06 2019 *)

A128376 Palindromic primes with only composite digits (i.e.,4,6,8,9).

Original entry on oeis.org

94649, 94849, 94949, 96469, 98689, 9446449, 9686869, 9888889, 9889889, 9896989, 9989899, 944999449, 946666649, 946999649, 948898849, 964444469, 964989469, 966848669, 968646869, 968666869, 968868869, 968898869, 968999869, 986444689
Offset: 1

Views

Author

Lekraj Beedassy, Feb 27 2007

Keywords

Comments

Subsequence of A128375.

Crossrefs

Cf. A002385, A083185.

Programs

  • Mathematica
    Select[Flatten[Table[FromDigits/@Tuples[{4,6,8,9},n],{n,9}]],PalindromeQ[ #] && PrimeQ[#]&] (* Harvey P. Dale, Dec 20 2018 *)

Extensions

Corrected by Ray Chandler, Feb 28 2007

A159471 Palindromic primes using only odd digits (1, 3, 5, 7 or 9).

Original entry on oeis.org

3, 5, 7, 11, 131, 151, 191, 313, 353, 373, 757, 797, 919, 11311, 13331, 13931, 15551, 17971, 19391, 19991, 31513, 33533, 35153, 35353, 35753, 37573, 71317, 71917, 75557, 77377, 77977, 79397, 79997, 93139, 93739, 95959, 97379, 97579, 1117111
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Apr 13 2009

Keywords

Links

Crossrefs

Cf. A002385, A083185.

Programs

  • Mathematica
    Table[Select[FromDigits/@Tuples[{1,3,5,7,9},n],PrimeQ[#]&& # == IntegerReverse[ #]&],{n,7}]//Flatten (* Harvey P. Dale, Sep 17 2016 *)

Extensions

Entries checked by R. J. Mathar, May 21 2010
Showing 1-4 of 4 results.

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

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