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.

A261018 First differences of A260273.

Original entry on oeis.org

2, 2, 3, 3, 4, 2, 3, 3, 4, 4, 2, 3, 3, 5, 7, 5, 5, 4, 3, 3, 5, 5, 3, 3, 4, 4, 4, 5, 7, 4, 5, 5, 4, 3, 3, 5, 5, 3, 3, 6, 8, 3, 3, 4, 4, 7, 4, 4, 5, 5, 5, 7, 7, 4, 5, 9, 5, 4, 4, 4, 3, 3, 3, 6, 3, 3, 6, 9, 5, 6, 5, 7, 8, 3, 3, 6, 3, 3, 4, 4, 4, 7, 4, 4, 8, 4, 4, 5, 5
Offset: 1

Views

Author

N. J. A. Sloane, Aug 17 2015

Keywords

Comments

a(n) = A261461(A260273(n)). - Reinhard Zumkeller, Aug 30 2015

Crossrefs

Programs

  • Haskell
    a261018 n = a261018_list !! (n-1)
    a261018_list = zipWith (-) (tail a260273_list) a260273_list
    -- Reinhard Zumkeller, Aug 30 2015
  • Mathematica
    b[1] = 1;
    b[n_] := b[n] = Module[{bits, k}, bits = IntegerDigits[b[n-1], 2]; For[k = 1, True, k++, If[SequencePosition[bits, IntegerDigits[k, 2]] == {}, Return[b[n-1] + k]]]];
    a[n_] := b[n+1] - b[n];
    Array[a, 100] (* Jean-François Alcover, Aug 02 2018 *)
  • Python
    A261018_list, a = [], 1
    for i in range(10**3):
        b, s = 1, format(a,'b')
        while format(b,'b') in s:
            b += 1
        a += b
        s = format(a,'b')
        A261018_list.append(b) # Chai Wah Wu, Aug 26 2015