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

1,2

Links

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

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 *)

Crossrefs

Cf. A004001, A005185.

Sequence in context: A032920 A134767 A022125 * A121226 A063633 A108933

Adjacent sequences: A121456 A121457 A121458 * A121460 A121461 A121462

Keyword

sign,less

Author

Roger L. Bagula, Sep 06 2006

Extensions

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

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

Status

approved