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.

A090712 Primes whose base-13 expansion is a (valid) decimal expansion of a prime.

Original entry on oeis.org

2, 3, 5, 7, 29, 53, 59, 79, 107, 113, 241, 263, 269, 293, 367, 373, 419, 443, 521, 523, 547, 601, 607, 631, 677, 757, 761, 787, 937, 971, 1021, 1069, 1093, 1231, 1249, 1277, 1307, 1361, 1381, 1433, 1459, 1543, 1567, 1613, 1619, 2213, 2237, 2239, 2447, 2477
Offset: 1

Views

Author

Cino Hilliard, Jan 18 2004

Keywords

Comments

See A235110 for a similar sequence whose definition works "in the opposite direction": Actually, the base-13 representation of the terms here. - M. F. Hasler, Jan 03 2014

Examples

			The prime p = 53 is written 41 in base 13, and 41 is again (the base 10 representation of) a prime. Therefore p = 53 is a term of this sequence. [Rephrased by _M. F. Hasler_, Jan 03 2014]
		

Crossrefs

Programs

  • Mathematica
    f[n_]:=Module[{c13=FromDigits[IntegerDigits[n],13]},If[PrimeQ[c13], c13,0]]; Select[f/@Prime[Range[500]],#!=0&] (* Harvey P. Dale, Jun 20 2011 *)
  • PARI
    is_A090712(p)=vecmax(d=digits(p,13))<10&&isprime(vector(#d,i,10^(#d-i))*d~)&&isprime(p) \\ M. F. Hasler, Jan 05 2014

Extensions

Edited by N. J. A. Sloane, Feb 07 2007, and by M. F. Hasler, Jan 05 2014