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 1-3 of 3 results.

A087593 Define dd(n) = the number formed by concatenating the absolute difference of successive digits. Sequence contains primes p such that dd(p) is also prime. (Primes in which the number formed by successive digit difference is also a prime.).

Original entry on oeis.org

13, 29, 31, 41, 47, 53, 61, 79, 83, 97, 101, 103, 107, 109, 113, 163, 227, 229, 241, 263, 269, 281, 307, 331, 347, 367, 401, 449, 463, 487, 503, 509, 521, 523, 541, 547, 557, 563, 569, 587, 601, 607, 641, 647, 661, 701, 709, 743, 769, 787, 809, 821, 823, 829
Offset: 0

Views

Author

Amarnath Murthy, Sep 18 2003

Keywords

Comments

Conjecture: Sequence is infinite. Subsidiary sequence: number of n-digit members.

Examples

			29 is a member as absolute(2-9) = 7 is a prime.
101 is a member as 1~0= 1, 0~1 = 1 and dd(101) = 11 is a prime.

Links

Crossrefs

Cf. A087594, A087595.

Programs

  • Mathematica
    Select[Prime[Range[200]],PrimeQ[FromDigits[Abs[Differences[ IntegerDigits[ #]]]]]&] (* Harvey P. Dale, Oct 10 2014 *)

Extensions

More terms from David Wasserman, Jun 15 2005

A087595 Smallest n-digit member of A087593. Define dd(k) = the number formed by concatenating the absolute difference of successive digits of k. Sequence contains smallest n-digit prime p such that dd(p) is also prime.

Original entry on oeis.org

13, 101, 1009, 10009, 100363, 1000003, 10000141, 100000543, 1000000007, 10000000589, 100000000447, 1000000000063, 10000000000609, 100000000000721, 1000000000000843, 10000000000002547, 100000000000000609
Offset: 2

Views

Author

Amarnath Murthy, Sep 18 2003

Keywords

Comments

Conjecture: Sequence is infinite.

Examples

			a(5) = 10009 and dd(10009) = 1009 is a prime.

Crossrefs

Cf. A087593, A087594, A087596.

Extensions

More terms from David Wasserman, Jun 15 2005

A087596 Largest n-digit member of A087593. Define dd(k) = the number formed by concatenating the absolute difference of successive digits of k. Sequence contains largest n-digit prime p such that dd(p) is also prime.

Original entry on oeis.org

97, 997, 9967, 99989, 999907, 9999907, 99999989, 999999607, 9999999967, 99999999947, 999999999989, 9999999999701, 99999999999923, 999999999999989, 9999999999999887, 99999999999999997, 999999999999999989
Offset: 2

Views

Author

Amarnath Murthy, Sep 18 2003

Keywords

Comments

Conjecture: Sequence is infinite.

Examples

			a(5) = 99989 and dd(99989) = 0011 = 11 is a prime.

Crossrefs

Cf. A087593, A087594, A087595.

Programs

  • Mathematica
    npr[n_]:=Module[{pr=NextPrime[10^n,-1]},While[!PrimeQ[FromDigits[Abs[ Differences[ IntegerDigits[pr]]]]],pr=NextPrime[pr,-1]];pr]; Array[ npr,20,2] (* Harvey P. Dale, Mar 06 2012 *)

Extensions

More terms from David Wasserman, Jun 15 2005
Showing 1-3 of 3 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.