OFFSET
1,2
COMMENTS
The positions of nonprime numbers in A037143.
The nonprime numbers A018252 which are not in A037143 do not contribute to the sequence and have no index of this kind. - R. J. Mathar, May 01 2010
MAPLE
From R. J. Mathar, May 01 2010: (Start)
A037143 := proc(n) option remember; if n = 1 then 1; else for a from procname(n-1)+1 do if numtheory[bigomega](a) <=2 then return a; end if; end do: end if; end proc:
A018252 := proc(n) option remember; if n = 1 then 1; else for a from procname(n-1)+1 do if not isprime(a) then return a; end if; end do: end if; end proc:
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Apr 19 2010
EXTENSIONS
Corrected (70 inserted) by R. J. Mathar, May 01 2010
STATUS
approved