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.

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A286706 Primes in A077309.

Original entry on oeis.org

23, 4567, 78910111213, 25262728293031323334353637383940414243444546474849
Offset: 1

Views

Author

XU Pingya, May 12 2017

Keywords

Comments

That is, primes formed from concatenation of k numbers starting with k.
Subsequence of A052087.
a(5) must be larger than A077309(2500).
A077309(k) is prime for k = {2, 4, 7, 25, ...}. - Michael De Vlieger, May 13 2017

Examples

			The prime 4567 is a term since it is the concatenation of 4 decimal numbers beginning with the number 4. - _Michael De Vlieger_, May 13 2017

Links

Crossrefs

Cf. A077309, A052087, A035333, A053067.

Programs

  • Mathematica
    Select[Table[FromDigits@ Flatten@ Take[#, {n, n + (n - 1)}], {n, Ceiling[Length[#]/2]}], PrimeQ] &@ Array[IntegerDigits, 10^3] (* Michael De Vlieger, May 13 2017 *)
Previous Showing 11-11 of 11 results.

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

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