cp's OEIS Frontend

A087758 Index of first occurrence of n in A005229.

%I A087758 #21 Jan 01 2024 11:19:59
%S A087758 1,3,4,6,7,8,10,12,13,14,16,17,19,20,21,22,24,26,27,29,31,32,33,34,36,
%T A087758 37,39,40,41,43,46,47,48,49,50,51,53,55,56,58,59,60,61,63,64,67,69,70,
%U A087758 71,72,73,74,75,77,80,81,82,83,85,87,88,89,90,92,94,95,98,99,100,102
%N A087758 Index of first occurrence of n in A005229.
%F A087758 a(n) = least k such that A005229(k) = n.
%o A087758 (True BASIC)
%o A087758 70 DIM q0(0 to 4000)
%o A087758 80 LET q0(1)=1
%o A087758 90 LET q0(2)=1
%o A087758 91 FOR n = 3 to 4000
%o A087758 92 LET q0(n)=q0(q0(n-2))+q0(n-q0(n-2))
%o A087758 93 NEXT n
%o A087758 100 SET MODE "color"
%o A087758 110 SET WINDOW 0,1024,0,750
%o A087758 302 PRINT" by _Roger L. Bagula_ 2 OCT. 2003"
%o A087758 303 DIM p(0 to 4000)
%o A087758 310 FOR x=1 to 4000
%o A087758 311 REM if p(q0(x)) hasn't been used already give p() a value
%o A087758 312 IF p(q0(x))=0 then LET p(q0(x))=x
%o A087758 380 NEXT x
%o A087758 381 OPEN #1: name "CM1:MI_data",create newold, org text
%o A087758 390 FOR x=1 to 200
%o A087758 391 PRINT #1: p(x);",";
%o A087758 392 PRINT p(x);
%o A087758 393 NEXT x
%o A087758 394 CLOSE #1
%o A087758 460 END
%o A087758 (PARI) {m=102;v5229=vector(m);v5229[1]=1;v5229[2]=1;for(k=3,m,v5229[k]=v5229[v5229[k-2]]+v5229[k-v5229[k-2]]); v=vector(m);for(j=1,m,if(v[v5229[j]]==0,v[v5229[j]]=j));n=0;while(v[n++ ]>0,print1(v[n],","))}
%Y A087758 Cf. A005229.
%K A087758 nonn
%O A087758 1,2
%A A087758 _Roger L. Bagula_, Oct 02 2003
%E A087758 Edited by _N. J. A. Sloane_, Apr 07 2006