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.

A073536 Breaking indices for A058842 (i.e., n such that A058842(n) is not equal to 3*A058842 (n-1) ).

Original entry on oeis.org

3, 9, 12, 15, 17, 27, 34, 39, 46, 49, 52, 54, 66, 70, 73, 81, 84, 90, 95, 102, 106, 110, 116, 119, 124, 132, 140, 143, 149, 153, 158, 161, 165, 171, 177, 180, 183, 186, 189, 194, 198, 209, 215, 221, 224, 226, 233, 235, 241, 244, 248, 251, 255, 259, 262, 272
Offset: 1

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Author

Benoit Cloitre, Aug 27 2002

Keywords

Crossrefs

Cf. A058842.

Formula

It seems that a(n) = 5*n +O(log(n)) and that a(n)=5*n for infinitely many values of n.
It appears that a(n)=A077468(n+1). - Benoit Cloitre, Jun 04 2004

A058840 From Renyi's "beta expansion of 1 in base 3/2": sequence gives y(0), y(1), ...

Original entry on oeis.org

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

Views

Author

Claude Lenormand (claude.lenormand(AT)free.fr), Jan 05 2001

Keywords

Comments

Let r be a real number strictly between 1 and 2, x any real number between 0 and 1; define y = (y(i)) by x(0) = x; x(i+1) = r*x(i)-1 if r*x(i)>1 and r*x(i) otherwise; y(i) = integer part of x(i+1): y = (y(i)) is an infinite word on the alphabet (0,1). Here we take r = 3/2 and x = 1.
Kempner considers a "canonical" expansion of a real number in a non-integer base using the greedy algorithm. The greedy algorithm takes the largest possible integer digit in the range 0 <= digit < base at each digit position from high to low. For base 3/2, Kempner gives the present sequence of digits, except instead a(1)=0, as an example canonical 2 = 10.01000001001... Kempner notes too that a(1) omitted and the rest shifted down is a base-3/2 non-canonical 1 = .101000001001.... (canonical would be 1 = 1.000...). - Kevin Ryde, Dec 06 2019

References

  • A. Renyi (1957), Representation for real numbers and their ergodic properties, Acta. Math. Acad. Sci. Hung., 8, 477-493.

Crossrefs

Programs

  • Haskell
    import Data.Ratio ((%), numerator, denominator)
    a058840 n = a058840_list !! n
    a058840_list = 1 : renyi' 1 where
       renyi' x = y : renyi' r  where
          (r, y) | q > 1     = (q - 1, 1)
                 | otherwise = (q, 0)
          q = 3%2 * x
    -- Reinhard Zumkeller, Jul 01 2011
    
  • Mathematica
    r = 3/2; x = 1; a[0] = a[1] = 1;
    For[n = 2, n<105, n++, x = If[r x > 1, r x - 1, r x]; a[n] = Floor[r x]];
    Table[a[n], {n, 0, 104}] (* Jean-François Alcover, Dec 21 2018, a solution I owe to Benoit Cloitre *)
  • PARI
    a_vector(len) = my(v=vector(len),c=2,d=1); for(i=1,len, if(c>=d,c-=d;v[i]=1); c*=3;d*=2); v; \\ Kevin Ryde, Dec 06 2019

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Feb 22 2001

A058841 From Renyi's "beta expansion of 1 in base 3/2": sequence gives lengths of runs of 0's in A058840.

Original entry on oeis.org

0, 1, 5, 2, 2, 1, 9, 6, 4, 6, 2, 2, 1, 11, 3, 2, 7, 2, 5, 4, 6, 3, 3, 5, 2, 4, 7, 7, 2, 5, 3, 4, 2, 3, 5, 5, 2, 2, 2, 2, 4, 3, 10, 5, 5, 2, 1, 6, 1, 5, 2, 3, 2, 3, 3, 2, 9, 6, 9, 6, 8, 2, 7, 5, 3, 2, 2, 4, 3, 1, 14, 9, 3, 6, 7, 3, 2, 2, 3, 4, 3, 2, 6, 4, 2
Offset: 0

Views

Author

Claude Lenormand (claude.lenormand(AT)free.fr), Jan 05 2001

Keywords

References

  • A. Renyi (1957), Representation for real numbers and their ergodic properties, Acta. Math. Acad. Sci. Hung., 8, 477-493.

Crossrefs

Programs

  • Haskell
    import Data.List (group)
    a058841 n = a058841_list !! n
    a058841_list =
       0 : (map length $ filter ((== 0) . head) $ group a058840_list)
    -- Reinhard Zumkeller, Jul 01 2011
  • Mathematica
    nmax = 500; r = 3/2; x = 1; (* b = A058840 *) b[0] = b[1] = 1;
    For[n=2, n <= nmax, n++, x = If[r x > 1, r x - 1, r x]; b[n] = Floor[r x]];
    Join[{0}, Length /@ Select[Split[Table[b[n], {n, 0, nmax}]], #[[1]] == 0&]] (* Jean-François Alcover, Dec 21 2018, using Benoit Cloitre's code for A058840 *)

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Feb 22 2001
Data corrected for n>33 by Reinhard Zumkeller, Jul 01 2011

A073533 Let x(1)=1, x(n+1) = (4/3)*x(n) - floor((4/3)*x(n)); then a(n)=x(n)*3^n.

Original entry on oeis.org

1, 4, 16, 64, 13, 52, 208, 832, 3328, 13312, 53248, 212992, 851968, 3407872, 13631488, 11479231, 45916924, 183667696, 734670784, 2938683136, 1294379341, 5177517364, 20710069456, 82840277824, 331361111296, 1325444445184
Offset: 1

Views

Author

Benoit Cloitre, Aug 27 2002

Keywords

Comments

It seems that the sequence x(n) = a(n)/3^n which satisfies 0 infinity sum(k=1,n,x(k))/n = C < 0.38 < 1/2
It appears that a(n) = 13*4^(n-5) for n > 4. - Creighton Dement, Nov 04 2004
This is not true, as a(16) mod 13 = 10. - Reinhard Zumkeller, Jun 05 2015

Crossrefs

Cf. A058842.

Programs

  • Haskell
    import Data.Ratio (numerator, (%))
    a073533 n = a073533_list !! (n-1)
    a073533_list = f 1 3 1 where
       f n p3 x = numerator(y * fromIntegral p3) : f (n + 1) (p3 * 3) y
                  where y = z - fromIntegral (floor z); z = 4%3 * x
    -- Reinhard Zumkeller, Jun 05 2015
Showing 1-4 of 4 results.