A094222 a(n+1) = a(n) + (number of distinct prime factors of a(n)) for n>1; a(1)=1, a(2)=2.

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 14, 16, 17, 18, 20, 22, 24, 26, 28, 30, 33, 35, 37, 38, 40, 42, 45, 47, 48, 50, 52, 54, 56, 58, 60, 63, 65, 67, 68, 70, 73, 74, 76, 78, 81, 82, 84, 87, 89, 90, 93, 95, 97, 98, 100, 102, 105, 108, 110, 113, 114, 117, 119, 121, 122, 124

Offset: 1

Author

Reinhard Zumkeller, May 28 2004

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A001221, A160649.

Programs

Maple

A094222 := proc(n)
    option remember;
    if n <= 2 then
        n;
    else
        procname(n-1)+A001221(procname(n-1)) ;
    end if;
end proc:
seq(A094222(n),n=1..30) ; # R. J. Mathar, Jul 09 2016

Mathematica

a[1] = 1; a[2] = 2; a[n_] := a[n] = a[n-1] + PrimeNu[a[n-1]]; Array[a, 66] (* Jean-François Alcover, Sep 13 2016 *)