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.

A262640 Base-10 representation of the primes at A262639.

Original entry on oeis.org

3, 29, 373, 104281, 26834329, 912643687, 1226640300497, 98267311812235733, 1020860032010008425847, 21115310556546915420698449, 1012916271690222867857136967, 26879969170345514485602194376469, 19901192726231131838758996344598879
Offset: 1

Views

Author

Clark Kimberling, Oct 24 2015

Keywords

Examples

			n   A262639(n)    base-10 representation
1     3                 3
2     131               29
3     11311             373
		

Crossrefs

Cf. A262639.

Programs

  • Mathematica
    s = {3}; base = 4; 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  (* A262639 *)
    Map[FromDigits[ToString[#], base] &, s]  (* A262640 *)
    (* 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 *)

A262642 Base-10 representation of 1 and the primes at A262641.

Original entry on oeis.org

1, 31, 2659, 28921, 20254277, 222258347161, 6703502508238897, 2849796577598550571, 163260594826469315359, 78587320839900014133983, 63082726980138277941240209, 28861909227691304085982177103, 17774573388934687063056536849453
Offset: 1

Views

Author

Clark Kimberling, Oct 24 2015

Keywords

Examples

			n   A262641(n)    base-10 representation
1     1                  1
2     111                31
3     41114              2659
		

Crossrefs

Cf. A262641.

Programs

  • Mathematica
    s = {3}; base = 4; 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  (* A262639 *)
    Map[FromDigits[ToString[#], base] &, s]  (* A262640 *)
    (* Peter J. C. Moses, Sep 01 2015 *)
Showing 1-3 of 3 results.