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.

A278696 Primes p such that every suffix of the ternary (base-3) representation of p is a prime.

Original entry on oeis.org

2, 5, 11, 23, 29, 59, 83, 167, 173, 191, 491, 509, 569, 653, 659, 677, 1481, 1487, 1949, 2027, 2111, 4397, 4457, 4547, 4943, 5051, 5861, 6323, 6563, 13127, 13151, 13313, 13613, 13691, 13781, 13799, 15149, 15233, 17519, 17579, 17669, 39371, 39857, 40847, 40853, 43913, 44417, 52517, 53147, 59051
Offset: 1

Views

Author

Randy L. Ekl, Nov 26 2016

Keywords

Comments

All numbers in the sequence are of one of the forms, base 3:
a. 2
b. 10...02, where there are 0 or more 0's
c. 20...0x, where there are 0 or more 0's, and x is of the form b or c
There is always exactly one 1 in the number, base 3.
All numbers end in a 2, base 3.

Examples

			569 is in the sequence, as 569=210002_3 and its base-3 suffixes are 10002_3=83 and 2_3=2, both of which are prime.
		

Crossrefs

Cf. A278694.

Programs

  • Maple
    F[1]:= [2]:
    for m from 2 to 11 do
      F[m]:= [op(F[m-1]),op(select(isprime, [seq(seq(i*3^
    (m-1)+x,x=F[m-1]),i=[1,2])]))]
    od:
    F[11]; # Robert Israel, Jan 22 2020