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

0, -3, -14, -18, -7, -9, -47, -51, 0, -15, -15, -48, -17, -36, 57, -151, 0, -63, 0, -11, 0, 25, 26, 368, 29, -5, -96, -33, 0, -144, 2275, -466, -180, 433, 472, 0, -43, 316, 0, 0, 47, -302, 49, 152, 1122, 945, 1273, 10170, 589, 1310, 121, 54, 3117, 0, 177, 2141, -1280, -5, 310, 0

Offset: 1

Author

Roger L. Bagula, Sep 06 2006

Keywords

• sign
• less

Links

• G. C. Greubel, Table of n, a(n) for n = 1..350

Crossrefs

Cf. A004001, A005185.

Programs

Mathematica

HConway[n_]:= HConway[n]= If[n<3, 1, HConway[HConway[n-1]] + HConway[n-HConway[n -1]]];
Hofstadter[n_]:= Hofstadter[n]= If[n<3, 1, Hofstadter[n -Hofstadter[n-1]] + Hofstadter[n -Hofstadter[n-2]]];
f[n_]:= f[n]= HConway[n]^2 - Hofstadter[n]^2;
Table[f[Abs[f[n-1]]] + f[Abs[n -f[n-1]]], {n,60}] (* corrected by G. C. Greubel, Feb 12 2020 *)

Extensions

Edited by N. J. A. Sloane, Oct 01 2006

Terms a(31) and beyond corrected by G. C. Greubel, Feb 12 2020