Van Eck sequence: Difference between revisions

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=={{header|Action!}}==

<lang Action!>INT FUNC LastPos(INT ARRAY a INT count,value)

INT pos

pos=count-1

WHILE pos>=0 AND a(pos)#value

DO

pos==-1

OD

RETURN (pos)

PROC Main()

DEFINE MAX="1000"

INT ARRAY seq(MAX)

INT i,pos

seq(0)=0

FOR i=1 TO MAX-1

DO

pos=LastPos(seq,i-1,seq(i-1))

IF pos>=0 THEN

seq(i)=i-1-pos

ELSE

seq(i)=0

FI

OD

PrintE("Van Eck first 10 terms:")

FOR i=0 TO 9

DO

PrintI(seq(i)) Put(32)

OD

PutE() PutE()

PrintE("Van Eck terms 991-1000:")

FOR i=990 TO 999

DO

PrintI(seq(i)) Put(32)

OD

RETURN</lang>

{{out}}

[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Van_Eck_sequence.png Screenshot from Atari 8-bit computer]

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Van Eck first 10 terms:

0 0 1 0 2 0 2 2 1 6

Van Eck terms 991-1000:

4 7 30 25 67 225 488 0 10 136