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A087826 a(n) = a(n-a(n-1))+a(a(n-a(n-2)) 0

%I

%S 1,1,2,2,3,3,3,5,4,5,5,5,8,5,7,7,8,8,8,8,13,7,10,10,10,10,13,12,11,13,

%T 13,13,13,21,8,15,12,15,18,12,16,18,18,15,21,18,16,21,20,18,21,26,21,

%U 18,25,20,20,22,20,19,25,20,25,25,17,27,20,28,24,26,28,23,31,31,22,31,28

%N a(n) = a(n-a(n-1))+a(a(n-a(n-2))

%C A version of Hofstadter Q triple recursion like A081831.

%C A 2nd type of triple recursion, a(n) = a(a(n-a(n-1)))+a(a(n-a(n-2)), works in Mathematica but not in true basic.

%o (TRUE BASIC) 60 REM HOFSTADTER'S triple 3rd BATRACHION SEQUENCE 70 DIM q0(0 to 4000) 80 LET q0(1)=1 90 LET q0(2)=1 91 FOR n = 3 to 4000 92 LET q0(n)=q0(n-q0(n-1))+q0(q0(n-q0(n-2))) 93 NEXT n 100 SET MODE "color" 110 SET WINDOW 0,1024,0,750 301 PRINT" Hofstadter triple recursion 3rd type" 302 PRINT" by Roger L. Bagula Oct 06 2003 " 381 open #1: name "CM1:Ht3_data",create newold, org text 390 FOR x=1 to 200 391 PRINT #1: q0(x);","; 392 NEXT x 393 close #1 460 END

%Y Cf. A004001, A081831.

%K nonn

%O 1,3

%A _Roger L. Bagula_, Oct 06 2003

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Last modified May 29 08:07 EDT 2022. Contains 354122 sequences. (Running on oeis4.)