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A121459 Let f(n) = A004001(n)^2 - A005185(n)^2. Then a(n) = f(abs(f(n-1))) + f(abs(n - f(n-1))). 1

%I #21 Feb 15 2020 03:45:41

%S 0,-3,-14,-18,-7,-9,-47,-51,0,-15,-15,-48,-17,-36,57,-151,0,-63,0,-11,

%T 0,25,26,368,29,-5,-96,-33,0,-144,2275,-466,-180,433,472,0,-43,316,0,

%U 0,47,-302,49,152,1122,945,1273,10170,589,1310,121,54,3117,0,177,2141,-1280,-5,310,0

%N Let f(n) = A004001(n)^2 - A005185(n)^2. Then a(n) = f(abs(f(n-1))) + f(abs(n - f(n-1))).

%H G. C. Greubel, <a href="/A121459/b121459.txt">Table of n, a(n) for n = 1..350</a>

%t HConway[n_]:= HConway[n]= If[n<3, 1, HConway[HConway[n-1]] + HConway[n-HConway[n -1]]];

%t Hofstadter[n_]:= Hofstadter[n]= If[n<3, 1, Hofstadter[n -Hofstadter[n-1]] + Hofstadter[n -Hofstadter[n-2]]];

%t f[n_]:= f[n]= HConway[n]^2 - Hofstadter[n]^2;

%t Table[f[Abs[f[n-1]]] + f[Abs[n -f[n-1]]], {n,60}] (* corrected by _G. C. Greubel_, Feb 12 2020 *)

%Y Cf. A004001, A005185.

%K sign,less

%O 1,2

%A _Roger L. Bagula_, Sep 06 2006

%E Edited by _N. J. A. Sloane_, Oct 01 2006

%E Terms a(31) and beyond corrected by _G. C. Greubel_, Feb 12 2020

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Last modified April 19 11:31 EDT 2024. Contains 371792 sequences. (Running on oeis4.)