RosettaCodeData/Task/Hofstadter-Q-sequence/ZX-Spectrum-Basic/hofstadter-q-sequence.basic

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10 PRINT "First 10 terms of Q = "
20 FOR i=1 TO 10: GO SUB 1000: PRINT s;" ";: NEXT i: PRINT
30 LET i=1000
40 PRINT "1000th term = ";: GO SUB 1000: PRINT s
50 PRINT "Term is less than preceding term ";c;" times"
100 STOP
1000 REM Qsequence subroutine
1010 IF i<3 THEN LET s=1: RETURN
1020 IF i=3 THEN LET s=2: RETURN
1030 DIM q(i)
1040 LET q(1)=1: LET q(2)=1: LET q(3)=2
1050 LET c=0
1060 FOR j=3 TO i
1070 LET q(j)=q(j-q(j-1))+q(j-q(j-2))
1080 IF q(j)<q(j-1) THEN LET c=c+1
1090 NEXT j
1100 LET s=q(i)
1110 RETURN