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 1-2 of 2 results.

A262636 Base-10 representation of 1 and the primes at A262635.

Original entry on oeis.org

1, 409, 88469, 3499607, 525755773, 1889074241401, 14476124563693171, 3690382506839631667, 944489835647492584243, 17945058791198905978063, 1798278215177468964031733, 17136765345945336793560989047, 39126270988987383599688999460333
Offset: 1

Views

Author

Clark Kimberling, Oct 02 2015

Keywords

Examples

			n   A262635(n)    base-10 representation
1   1             1
2   12121         409
3   111212111     88469
		

Crossrefs

Cf. A262635. Subsequence of A029972.

Programs

  • Mathematica
    s = {1}; 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  (* A262635 *)
    Map[FromDigits[ToString[#], base] &, s]  (* A262636 *)
    (* 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 *)
Showing 1-2 of 2 results.