A087814 Sequence gives A087655(n) for those n such that A087655(n) = A087655(n+1).

1, 1, 13, 15, 25, 39, 47, 51, 69, 81, 101, 139, 249, 261, 275, 291, 739, 1243, 2243

Offset: 0

Author

Roger L. Bagula, Oct 05 2003

Keywords

• nonn

Crossrefs

Cf. A087655.

Programs

Mathematica

Hofstadter123[n_Integer?Positive] := Hofstadter123[n] = Hofstadter123[Abs[n - Hofstadter123[n-1]]] + Hofstadter123[Abs[n - Hofstadter123[n-2]]]+ Hofstadter123[Abs[n - Hofstadter123[n-3]]] Hofstadter123[0] =Hofstadter123[1] = Hofstadter123[2]= Hofstadter123[3]= 1 digits=30000 ta=Table[Hofstadter123[n], {n, 1, digits}]; b=Table[If[ta[[n]]-ta[[n-1]]==0, ta[[n]], 0], {n, 2, digits}]; c=Delete[Union[b], 1]