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.

A100580 Palindromic primes containing digits 0 and 1 only. (Palindromic terms in A020449.)

Original entry on oeis.org

11, 101, 100111001, 110111011, 111010111, 1100011100011, 1100101010011, 1101010101011, 1110110110111, 1110111110111, 100110101011001, 101000010000101, 101011000110101, 101110000011101, 110011101110011
Offset: 1

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Author

Chuck Seggelin (seqfan(AT)plastereddragon.com), Nov 29 2004

Keywords

Examples

			a(3) = 100111001 because 100111001 is the third palindromic prime composed only of 1's and 0's.
		

Crossrefs

Programs

  • Mathematica
    PalQ[n_]:=FromDigits[Reverse@IntegerDigits[n]]==n; DeleteDuplicates[Flatten[Table[Select[FromDigits /@ Tuples[{0,1},n],PrimeQ[#]&&PalQ[#] &],{n,15}]]] (* Jayanta Basu, May 11 2013 *)
    Select[FromDigits/@Tuples[{0,1},15],PalindromeQ[#]&&PrimeQ[#]&] (* Harvey P. Dale, Jan 18 2023 *)
  • Python
    from sympy import isprime
    A100580_list = [11]
    for i in range(2, 2**16):
        s = format(i, 'b')
        x = int(s+s[-2::-1])
        if isprime(x):
            A100580_list.append(x) # Chai Wah Wu, Jan 06 2015