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 A087826 a(n) = a(n-a(n-1))+a(a(n-a(n-2)) 0
 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, 13, 13, 13, 21, 8, 15, 12, 15, 18, 12, 16, 18, 18, 15, 21, 18, 16, 21, 20, 18, 21, 26, 21, 18, 25, 20, 20, 22, 20, 19, 25, 20, 25, 25, 17, 27, 20, 28, 24, 26, 28, 23, 31, 31, 22, 31, 28 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS A version of Hofstadter Q triple recursion like A081831. 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. LINKS PROG (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 CROSSREFS Cf. A004001, A081831. Sequence in context: A318082 A318350 A127332 * A131624 A165077 A165079 Adjacent sequences:  A087823 A087824 A087825 * A087827 A087828 A087829 KEYWORD nonn AUTHOR Roger L. Bagula, Oct 06 2003 STATUS approved

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Last modified January 29 03:01 EST 2022. Contains 350672 sequences. (Running on oeis4.)