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

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

Author

Reinhard Zumkeller, Jul 12 2001

Keywords

• easy
• nice
• nonn

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

Links

• R. Zumkeller, Table of n, a(n) for n = 0..10000

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 *)