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 1-4 of 4 results.

A004685 Fibonacci numbers written in base 2.

Original entry on oeis.org

0, 1, 1, 10, 11, 101, 1000, 1101, 10101, 100010, 110111, 1011001, 10010000, 11101001, 101111001, 1001100010, 1111011011, 11000111101, 101000011000, 1000001010101, 1101001101101, 10101011000010, 100010100101111, 110111111110001, 1011010100100000, 10010010100010001
Offset: 0

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Author

Keywords

Crossrefs

Cf. A004686 .. A004694: Fibonacci numbers written in base 3, 4, ..., 13.
Cf. A004676 .. A004684: Primes written in base 2, 3, 4, ..., 11.
Cf. A004643, ..., A004668 : powers of 2 resp. of 3 in base 3, 4, 5, ..., 26.

Programs

  • Magma
    [Seqint(Intseq(Fibonacci(n),2)): n in [0..50]]; // G. C. Greubel, Oct 09 2018
  • Maple
    with(combinat): seq(convert(fibonacci(n),binary),n=0..25); # Muniru A Asiru, Oct 10 2018
  • Mathematica
    Table[FromDigits[IntegerDigits[Fibonacci[n], 2]], {n, 0, 30}] (* Stefan Steinerberger, Apr 14 2006 *)
  • PARI
    a(n)=subst(Pol(binary(fibonacci(n))),'x,10) \\ Charles R Greathouse IV, Feb 03 2014
    
  • PARI
    apply( n->fromdigits(binary(fibonacci(n))), [0..19]) \\ M. F. Hasler, Jun 22 2018
    
  • PARI
    vector(50, n, n--; fromdigits(digits(fibonacci(n), 2))) \\ G. C. Greubel, Oct 09 2018
    

Formula

a(n) = A007088(A000045(n)). - Jonathan Vos Post, Aug 24 2010

A030363 Write (n+1)st Fibonacci number in base 3 and juxtapose.

Original entry on oeis.org

1, 2, 1, 0, 1, 2, 2, 2, 1, 1, 1, 2, 1, 0, 1, 0, 2, 1, 2, 0, 0, 1, 1, 0, 0, 2, 2, 1, 2, 1, 0, 0, 2, 2, 1, 2, 2, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 2, 1, 1, 1, 0, 0, 1, 2, 0, 2, 0, 1, 2, 0, 1, 1, 1, 0, 1, 1, 2, 2, 0, 1, 1, 2, 2, 0, 1, 2, 1, 2, 1, 0, 0, 0, 2, 1, 1, 2, 0, 1, 2
Offset: 1

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Author

Keywords

Crossrefs

Cf. A004686 (Fibonacci numbers written in base 3).

Programs

  • Mathematica
    Flatten[IntegerDigits[Fibonacci[Range[2,30]],3]] (* Harvey P. Dale, Apr 09 2015 *)

A214326 Square array read by antidiagonals in which T(n,b) gives the n-th Fibonacci number written in base b with n,b >= 1.

Original entry on oeis.org

1, 1, 1, 1, 1, 11, 1, 1, 10, 111, 1, 1, 2, 11, 11111, 1, 1, 2, 10, 101, 11111111, 1, 1, 2, 3, 12, 1000, 1111111111111, 1, 1, 2, 3, 11, 22, 1101, 111111111111111111111, 1, 1, 2, 3, 10, 20, 111, 10101, 1111111111111111111111111111111111, 1, 1, 2, 3, 5, 13, 31, 210, 100010
Offset: 1

Views

Author

Alois P. Heinz, Jul 24 2012

Keywords

Comments

For b > 10, some terms cannot be properly notated using only decimal characters.

Examples

			Square array A(n,b) begins:
              1,    1,   1,  1,  1,  1,  1,  1,  1,  1,  1,  1, ...
              1,    1,   1,  1,  1,  1,  1,  1,  1,  1,  1,  1, ...
             11,   10,   2,  2,  2,  2,  2,  2,  2,  2,  2,  2, ...
            111,   11,  10,  3,  3,  3,  3,  3,  3,  3,  3,  3, ...
          11111,  101,  12, 11, 10,  5,  5,  5,  5,  5,  5,  5, ...
       11111111, 1000,  22, 20, 13, 12, 11, 10,  8,  8,  8,  8, ...
  1111111111111, 1101, 111, 31, 23, 21, 16, 15, 14, 13, 12, 11, ...
		

Crossrefs

Programs

  • Maple
    A:= proc(n, b) local f, l; f:= combinat[fibonacci](n);
          if b=1 then parse(cat(1$f))
        else l:= NULL;
             while f>0 do l:= irem(f, b, 'f'), l od;
             parse(cat(l))
          fi
        end:
    seq(seq(A(n, 1+d-n), n=1..d), d=1..10);

A111064 Numbers n such that the sum of the digits of the n-th Fibonacci number written in bases 2, 3, 5 and 7 is prime.

Original entry on oeis.org

7, 8, 10, 17, 47, 61, 70, 170, 185, 299, 766, 950, 1247, 1669, 1879, 2063, 2090, 2701, 3071, 5809, 6190, 7057, 7409, 8410, 12754, 13303, 13421, 14533, 16250, 18793, 24766, 24895, 27370, 28594, 28870, 29093, 29189, 30647, 31481, 36334, 38123, 38957
Offset: 1

Views

Author

Stefan Steinerberger, Nov 12 2005

Keywords

Examples

			21 is the 8th Fibonacci number. Written in bases 2,3,5,7 we obtain 10101, 210, 41 and 30. The sum of the digits of each of this representations is prime, so 8 is an element of the sequence.
		

Crossrefs

Programs

  • Mathematica
    fQ[n_] := Union@PrimeQ[Plus @@@ IntegerDigits[ Fibonacci@n, {2, 3, 5, 7}]] == {True}; Select[ Range[39285], fQ[ # ] &] (* Robert G. Wilson v *)
    Select[Range[40000],AllTrue[Total/@IntegerDigits[Fibonacci[#],{2,3,5,7}],PrimeQ]&] (* Harvey P. Dale, Sep 09 2021 *)
  • MuPAD
    for n from 1 to 1500 do a := numlib::fibonacci(n); if numlib::proveprime(numlib::sumOfDigits(a,2)) = TRUE then if numlib::proveprime(numlib::sumOfDigits(a,3)) = TRUE then if numlib::proveprime(numlib::sumOfDigits(a,5)) = TRUE then if numlib::proveprime(numlib::sumOfDigits(a,7)) = TRUE then print(n); end_if; end_if; end_if; end_if; end_for;

Extensions

More terms from Robert G. Wilson v, Nov 14 2005
Corrected by Harvey P. Dale, Sep 09 2021
Showing 1-4 of 4 results.