login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A087722 Strictly decreasing domain set of the Hofstadter batrachian sequence A005185. 1

%I

%S 9,14,17,19,21,24,26,28,30,31,33,35,37,39,40,41,43,44,46,48,50,52,53,

%T 55,57,58,61,62,63,64,65,68,69,71,72,73,75,76,77,78,79,82,83,84,86,87,

%U 88,90,92,93,94,100,104,105,106,107,108,109,110,112,113,114,116,118,119

%N Strictly decreasing domain set of the Hofstadter batrachian sequence A005185.

%C The third set of the Hofstadter domain.

%F a[n] =a[n - a[n-1]] + a[n - a[n-2]]

%t digits=750 Hofstadter[n_Integer?Positive] := Hofstadter[n] = Hofstadter[n - Hofstadter[n-1]] + Hofstadter[n - Hofstadter[n-2]] Hofstadter[1] = Hofstadter[2] = 1 a1=Table[Hofstadter[n], {n, 1, digits}]; f[x_, y_] := Abs[x-y]/; x-y<0 f[x_, y_] := 0/; x-y>=0 b=Table[If[f[a1[[n]], a1[[n-1]]]>0, a1[[n]], 0], {n, 2, digits}]; c=Delete[Union[b], 1]

%Y Cf. A005185.

%K nonn

%O 1,1

%A _Roger L. Bagula_, Sep 29 2003

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 17 19:58 EDT 2021. Contains 347489 sequences. (Running on oeis4.)