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 1-3 of 3 results.

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
    

A261644 Distance of A260273(n) to next power of 2.

Original entry on oeis.org

1, 1, 3, 8, 5, 1, 15, 12, 9, 5, 1, 31, 28, 25, 20, 13, 8, 3, 63, 60, 57, 52, 47, 44, 41, 37, 33, 29, 24, 17, 13, 8, 3, 127, 124, 121, 116, 111, 108, 105, 99, 91, 88, 85, 81, 77, 70, 66, 62, 57, 52, 47, 40, 33, 29, 24, 15, 10, 6, 2, 254, 251, 248, 245, 239
Offset: 1

Views

Author

Reinhard Zumkeller, Aug 30 2015

Keywords

Comments

This sequence, as well as A261712, is suggested by A261396 and A261416.

Examples

			.  1: 1
.  2: 1
.  3: 3
.  4: 8,5,1
.  5: 15,12,9,5,1
.  6: 31,28,25,20,13,8,3
.  7: 63,60,57,52,47,44,41,37,33,29,24,17,13,8,3
.  8: 127,124,121,116,111,108,105,99,91,88,85,81,77,70,... (27 terms)
.  9: 254,251,248,245,239,236,233,227,218,213,207,202,195,,... (49 terms)
		

Crossrefs

Cf. A260273, A062383, A261645 (first differences), A261712 (reversed), A261646 (row lengths).

Programs

  • Haskell
    a261644 n = a261644_list !! (n-1)
    a261644_list = zipWith (-)
                   (map a062383 a260273_list) $ map fromIntegral a260273_list
    a261644_tabf = [1] : f (tail $ zip a261645_list a261644_list) where
       f dxs = (map snd (dxs'' ++ [dx])) : f dxs' where
         (dxs'', dx:dxs') = span ((<= 0) . fst) dxs
    a261644_row n = a261644_tabf !! (n-1)

Formula

a(n) = A062383(A260273(n)) - A260273(n).

A261789 First differences of A261786.

Original entry on oeis.org

2, 2, 3, 1, 2, 4, 3, 1, 3, 3, 3, 2, 2, 4, 2, 5, 3, 3, 3, 3, 3, 3, 3, 4, 3, 3, 1, 4, 3, 2, 2, 4, 2, 4, 4, 4, 4, 2, 5, 5, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 3, 3, 4, 3, 3, 3, 3, 4, 3, 3, 1, 4, 3, 4, 4, 5, 3, 3, 3, 3, 3, 1, 4, 3, 4, 3, 3, 1, 4, 3, 2, 2, 4, 2, 4, 4
Offset: 1

Views

Author

Reinhard Zumkeller, Sep 01 2015

Keywords

Comments

a(n) = A261787(A261786(n)).

Crossrefs

Programs

  • Haskell
    a261789 n = a261789_list !! (n-1)
    a261789_list = zipWith (-) (tail a261786_list') a261786_list'
Showing 1-3 of 3 results.