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.

A262646 Base-10 representation of 0 and the primes at A262645.

Original entry on oeis.org

0, 37, 242399, 99425647, 2773336219, 95004181411, 6926597956637167, 25520724664154228141, 238868280677120302172737, 18101838945984695191070222173, 578712262382613259078341544982179, 20796546496637158906389193655535571
Offset: 1

Views

Author

Clark Kimberling, Oct 24 2015

Keywords

Examples

			n   A262645(n)    base-10 representation
1      0                 0
2      101               37
3      5110115           242399
		

Crossrefs

Cf. A262645.

Programs

  • Mathematica
    s = {0}; base = 6; z = 20; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#, base]], base]] &];
    AppendTo[s, FromDigits[IntegerDigits[tmp, base]]], {z}]; s  (* A262645 *)
    Map[FromDigits[ToString[#], base] &, s]  (* A262646 *)
    (* Peter J. C. Moses, Sep 01 2015 *)

A262627 Minimal nested base-2 palindromic primes with seed 0.

Original entry on oeis.org

0, 101, 11001010011, 101100101001101, 10101011001010011010101, 111010101100101001101010111, 1111101010110010100110101011111, 101111111010101100101001101010111111101, 110101111111010101100101001101010111111101011
Offset: 1

Views

Author

Clark Kimberling, Oct 02 2015

Keywords

Comments

Using only base-2 digits 0 and 1, let s be a palindrome and put a(1) = s. Let a(2) be the least palindromic prime having s in the middle; for n > 2, let a(n) be the least palindromic prime have a(n-1) in the middle. Then (a(n)) is the sequence of minimal nested base-2 palindromic primes with seed s -- a(1) being not prime, of course.
Guide to related sequences
base seed base-b repr. base-10 repr.

Examples

			a(3) = 11001010011 =A117697(15) is the least prime having a(2) = 101 in its middle. Triangular format:
               0
              101
          11001010011
        101100101001101
    10101011001010011010101
  111010101100101001101010111
1111101010110010100110101011111
		

Crossrefs

Cf. A117697, A261881 (base 10), A262628-A262662.

Programs

  • Mathematica
    s = {0}; base = 2; z = 20; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#, base]], base]] &];
    AppendTo[s, FromDigits[IntegerDigits[tmp, base]]], {z}]; s  (* A262627 *)
    Map[FromDigits[ToString[#], base] &, s]  (* A262628 *)
    (* Peter J. C. Moses, Sep 01 2015 *)

A262648 Base-10 representation of 0 and the primes at A262647.

Original entry on oeis.org

1, 43, 55987, 102792517, 95125388731, 3981385394034229, 27783887681061330839, 7141162170983023407421, 40050387387887393264626841, 400599026018424027699693461857, 2500775549161597801615214316269999, 35465901730059327498617881373769591811
Offset: 1

Views

Author

Clark Kimberling, Oct 25 2015

Keywords

Examples

			n   A262647(n)    base-10 representation
1     1                  1
2     111                43
3     1111111            55987
		

Crossrefs

Cf. A262647.

Programs

  • Mathematica
    s = {1}; base = 6; z = 20; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#, base]], base]] &];
    AppendTo[s, FromDigits[IntegerDigits[tmp, base]]], {z}]; s  (* A262645 *)
    Map[FromDigits[ToString[#], base] &, s]  (* A262646 *)
    (* Peter J. C. Moses, Sep 01 2015 *)
Showing 1-3 of 3 results.