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%I #28 Dec 18 2022 02:31:32
%S 1,1,1,1,1,1,2,3,4,5,6,7,8,9,9,9,9,10,10,10,10,10,11,11,11,11,11,11,
%T 12,13,14,15,15,15,15,15,15,16,17,18,20,20,20,20,20,20,20,21,22,23,26,
%U 26,26,26,26,26,26,26,27
%N Tri-recursive sequence: a(n) = a(a(a(n-1))) + a(n - a(a(-3+n))) if n>6, otherwise a(n) = 1.
%C a(n-1) <= a(n) for n <= 64, but a(65)-a(64) = 32-35 < 0; first positions m where a(m) > a(m+1): 64, 79, 84, 99, 105, 106, 110, 125, 126, ... . - _Reinhard Zumkeller_, Jun 13 2013
%H Reinhard Zumkeller, <a href="/A185137/b185137.txt">Table of n, a(n) for n = 1..10000</a>
%H <a href="/index/Ho#Hofstadter">Index entries for Hofstadter-type sequences</a>
%t a[1] = 1; a[2] = 1; a[3] = 1; a[4] = 1; a[5] = 1; a[6] = 1;
%t a[n_] := a[n] = a[a[a[n - 1]]] + a[n - a[a[-3 + n]]]
%t Table[a[n], {n, 1, 300}]
%o (Haskell)
%o a185137 n = a185137_list !! (n-1)
%o a185137_list = 1 : 1 : 1 : 1 : 1 : 1 : f 7 1 1 where
%o f x u v = w : f (x + 1) v w where
%o w = (a185137 . a185137 . a185137) (x - 1) +
%o a185137 (x - (a185137 . a185137) (x - 3))
%o -- _Reinhard Zumkeller_, Jun 13 2013
%Y Cf. A209384, A087831.
%K nonn,look
%O 1,7
%A _Roger L. Bagula_, Mar 12 2012
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