Stern-Brocot sequence: Difference between revisions

=={{header|MAD}}==

<lang MAD> NORMAL MODE IS INTEGER

VECTOR VALUES FRST15 = $20HFIRST 15 NUMBERS ARE*$

VECTOR VALUES FRSTAT = $6HFIRST ,I3,S1,11HAPPEARS AT ,I4*$

VECTOR VALUES NUMBER = $I4*$

DIMENSION STERN(1200)

STERN(1) = 1

STERN(2) = 1

R GENERATE FIRST 1200 MEMBERS OF THE STERN-BROCOT SEQUENCE

THROUGH GENSEQ, FOR I = 1, 1, I .GE. 600

STERN(I*2-1) = STERN(I) + STERN(I-1)

GENSEQ STERN(I*2) = STERN(I)

R PRINT FIRST 15 VALUES OF STERN-BROCOT SEQUENCE

PRINT FORMAT FRST15

THROUGH P15, FOR I = 1, 1, I .G. 15

P15 PRINT ON LINE FORMAT NUMBER, STERN(I)

R PRINT FIRST OCCURRENCE OF 1..10

THROUGH FRST10, FOR I = 1, 1, I .G. 10

FRST10 PRINT FORMAT FRSTAT, I, FIRST.(I)

PRINT FORMAT FRSTAT, 100, FIRST.(100)

R SEARCH FOR FIRST OCCURRENCE OF N IN SEQUENCE

INTERNAL FUNCTION(N)

ENTRY TO FIRST.

THROUGH SCAN, FOR K = 1, 1, I .G. 1200

SCAN WHENEVER N .E. STERN(K), FUNCTION RETURN K

END OF FUNCTION

END OF PROGRAM</lang>

{{out}}

<pre style="height: 45ex;">FIRST 15 NUMBERS ARE

1

1

2

1

3

2

3

1

4

3

5

2

5

3

4

FIRST 1 APPEARS AT 1

FIRST 2 APPEARS AT 3

FIRST 3 APPEARS AT 5

FIRST 4 APPEARS AT 9

FIRST 5 APPEARS AT 11

FIRST 6 APPEARS AT 33

FIRST 7 APPEARS AT 19

FIRST 8 APPEARS AT 21

FIRST 9 APPEARS AT 35

FIRST 10 APPEARS AT 39

FIRST 100 APPEARS AT 1179</pre>