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.
%I A059983 #8 Jul 13 2013 12:02:37
%S A059983 1,0,6,7,8,9,12,13,14,15,18,19,22,23,24,25,28,29,32,33,36,37,40,41,42,
%T A059983 43,46,47,50,51,54,55,58,59,62,63,66,67,70,71,74,75,76,77,80,81,84,85,
%U A059983 88,89,92,93,96,97,100,101,104,105,108,109,112,113,116,117,120,121,124
%N A059983 First occurrence of n in A007599.
%H A059983 Reinhard Zumkeller, <a href="/A059983/b059983.txt">Table of n, a(n) for n = 0..10000</a>
%e A059983 a(5) does not appear in A007599 until the 9th entry, keeping in mind the offset.
%t A059983 a[n_Integer] := a[n] = (a[n - 1] + Nest[a, n - 2, Floor[n/2] ] ); a[0] = 1; a[1] = 0; b[n_Integer] := (k = 0; While[ a[k] != n, k++ ]; k); Table[ b[n], {n, 0, 75} ]
%o A059983 (Haskell)
%o A059983 import Data.List (elemIndex)
%o A059983 import Data.Maybe (mapMaybe)
%o A059983 a059983 n = a059983_list !! n
%o A059983 a059983_list = mapMaybe (`elemIndex` a007599_list) [0..]
%o A059983 -- _Reinhard Zumkeller_, Jan 05 2012
%Y A059983 Cf. A007599.
%K A059983 nonn
%O A059983 0,3
%A A059983 _Robert G. Wilson v_, Mar 07 2001