Stern-Brocot sequence: Difference between revisions

=={{header|BASIC}}==

<lang basic>10 DEFINT A,B,I,J,S: DIM S(1200)

20 S(1)=1: S(2)=1

30 FOR I=2 TO 600

40 S(I*2-1)=S(I)+S(I-1)

50 S(I*2)=S(I)

60 NEXT I

70 PRINT "First 15 elements: ";

80 FOR I=1 TO 15: PRINT USING"# ";S(I);: NEXT I

85 PRINT

90 FOR I=1 TO 10

100 FOR J=1 TO 1200: IF S(J)<>I THEN NEXT J

110 PRINT "First";I;"at";J

120 NEXT I

130 FOR J=1 TO 1200: IF S(J)<>100 THEN NEXT J

140 PRINT "First 100 at";J

150 FOR I=2 TO 1000

160 A=S(I): B=S(I-1)

170 J=A: A=B: B=J MOD A: IF B THEN 170

180 IF A<>1 THEN PRINT "GCD <> 1 at ";I: STOP

190 NEXT I

200 PRINT "All GCDs are 1."

210 END</lang>

{{out}}

<pre>First 15 elements: 1 1 2 1 3 2 3 1 4 3 5 2 5 3 4

First 1 at 1

First 2 at 3

First 3 at 5

First 4 at 9

First 5 at 11

First 6 at 33

First 7 at 19

First 8 at 21

First 9 at 35

First 10 at 39

First 100 at 1179

All GCDs are 1.

</pre>