A007599 a(n+1) = a(n)+a(a(a(..(n-1)..))), depth [ n/2 ].

1, 0, 1, 1, 1, 1, 2, 3, 4, 5, 5, 5, 6, 7, 8, 9, 9, 9, 10, 11, 11, 11, 12, 13, 14, 15, 15, 15, 16, 17, 17, 17, 18, 19, 19, 19, 20, 21, 21, 21, 22, 23, 24, 25, 25, 25, 26, 27, 27, 27, 28, 29, 29, 29, 30, 31, 31, 31, 32, 33, 33, 33, 34, 35, 35, 35, 36, 37, 37, 37, 38, 39, 39, 39, 40

Offset: 0

Author

N. J. A. Sloane, Mira Bernstein, Robert G. Wilson v

Keywords

• nonn
• nice
• easy

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• T. D. Noe, Table of n, a(n) for n = 0..1000

Programs

Haskell

a007599 n = a007599_list !! n
a007599_list = 1 : f 1 1  where
   f x m = y : f y (m + 1) where
     y = x + (iterate a007599 (m-2)) !! (m `div` 2)
-- Reinhard Zumkeller, Jan 05 2012

Mathematica

a[n_Integer] := a[n] = (a[n - 1] + Nest[a, n - 2, Floor[n/2] ] ); a[0] = 1; a[1] = 0; Table[ a[n], {n, 0, 75} ]