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.

A062039 a(0) = 1; a(n+1) = a(n) - n if a(n) > n, otherwise a(n+1) = a(n) + a(a(n)).

Original entry on oeis.org

1, 1, 2, 4, 1, 2, 4, 5, 7, 12, 3, 7, 12, 24, 11, 18, 3, 7, 12, 24, 5, 7, 12, 24, 1, 2, 4, 5, 7, 12, 24, 25, 27, 32, 59, 25, 27, 32, 59, 21, 28, 35, 60, 18, 30, 54, 9, 21, 28, 35, 60, 10, 13, 37, 69, 15, 33, 65, 8, 15, 33, 65, 4, 5, 7, 12, 24, 25, 27, 32, 59, 74, 3, 7, 12, 24, 25, 27
Offset: 0

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Author

Reinhard Zumkeller, Jul 12 2001

Keywords

Comments

a(A193854(n)) = 1, n>0;
A123643 and A123644 give record values and their positions: A123643(n)=a(A123644(n)). - Reinhard Zumkeller, Oct 04 2006

Crossrefs

A123643 and A123644 give record values and their positions: A123643(n)=a(A123644(n)).
Cf. A193926 (first differences), A193927.

Programs

  • Haskell
    a062039 n = a062039_list !! n
    a062039_list = 1 : f 1 0 where
       f x n | x > n     = (x-n) : f (x-n) (n+1)
             | otherwise =    x' : f x' (n+1) where x' = x + a062039 x
    -- Reinhard Zumkeller, Aug 10 2011
  • Mathematica
    a[0] = 1; a[n_] := a[n] = If[a[n-1] > n-1, a[n-1] - (n-1), a[n-1] + a[a[n-1]]]; Table[a[n], {n, 0, 77}] (* Jean-François Alcover, Mar 20 2011 *)

A193926 First differences of A062039.

Original entry on oeis.org

0, 1, 2, -3, 1, 2, 1, 2, 5, -9, 4, 5, 12, -13, 7, -15, 4, 5, 12, -19, 2, 5, 12, -23, 1, 2, 1, 2, 5, 12, 1, 2, 5, 27, -34, 2, 5, 27, -38, 7, 7, 25, -42, 12, 24, -45, 12, 7, 7, 25, -50, 3, 24, 32, -54, 18, 32, -57, 7, 18, 32, -61, 1, 2, 5, 12, 1, 2, 5, 27, 15
Offset: 0

Views

Author

Reinhard Zumkeller, Aug 10 2011

Keywords

Comments

a(n) = A062039(n+1) - A062039(n);
a(A193927(n)) = - A193927(n).

Programs

  • Haskell
    a193926 n = a193926_list !! n
    a193926_list = zipWith (-) (tail a062039_list) a062039_list

A193928 Numbers m such that A062039(m) <= A062039(m+1).

Original entry on oeis.org

0, 1, 2, 4, 5, 6, 7, 8, 10, 11, 12, 14, 16, 17, 18, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 39, 40, 41, 43, 44, 46, 47, 48, 49, 51, 52, 53, 55, 56, 58, 59, 60, 62, 63, 64, 65, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82
Offset: 1

Views

Author

Reinhard Zumkeller, Aug 10 2011

Keywords

Comments

Complement of A193927, A062039(a(n)) <= A062039(a(n)+1).

Crossrefs

A193854 is a subsequence.

Programs

  • Haskell
    import Data.List (findIndices)
    a193928 n = a193928_list !! (n-1)
    a193928_list = findIndices (0 <=) a193926_list
Showing 1-3 of 3 results.