OFFSET
1,1
EXAMPLE
If i=1, then c(c(c(1)-3)-3)-3=c(c(4-3)-3)-3=c(4-3)-3=4-3=1 (nonprime).
If i=2, then c(c(c(2)-3)-3)-3=c(c(6-3)-3)-3=c(8-3)-3=c(5)-3=10-3=7=a(1).
MAPLE
A002808 := proc(n) option remember ; if n = 1 then 4; else for a from procname(n-1)+1 do if not isprime(a) then RETURN(a); fi; od: fi; end: rep := 3: for n from 1 to 800 do arep := n ; for i from 1 to rep do arep := A002808(arep)-3 ; od: if isprime(arep) then printf("%d, ", arep) ; fi; od: # R. J. Mathar, Sep 05 2008
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Sep 03 2008
EXTENSIONS
Removed erroneous examples, correctly roughly 10 percent of the values. - R. J. Mathar, Sep 05 2008
STATUS
approved