OFFSET
1,1
LINKS
N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]
FORMULA
Let C(n) be the n-th composite number, with C(1)=4. Then these are numbers C(C(C(n))).
EXAMPLE
C(C(C(8))) = C(C(15)) = C(25) = 38. So 38 is in the sequence.
MAPLE
C := remove(isprime, [$4..1000]): seq(C[C[C[C[n]]]], n=1..100);
MATHEMATICA
Nest[Values@ KeySelect[MapIndexed[First@ #2 -> #1 &, #], CompositeQ] &, Select[Range@ 150, CompositeQ], 2] (* Michael De Vlieger, Jul 22 2017 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Michael Lugo (mlugo(AT)thelabelguy.com), Dec 22 1999
EXTENSIONS
More terms from Asher Auel Dec 15 2000
STATUS
approved