OFFSET
1,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Eckford Cohen, Some asymptotic formulas in the theory of numbers, Transactions of the American Mathematical Society, Vol. 112, No. 2, (1964), pp. 214-227.
Willy Feller and Erhard Tornier, Mengentheoretische Untersuchung von Eigenschaften der Zahlenreihe, Mathematische Annalen, Vol. 107, No. 1 (1933), pp. 188-232.
I. J. Schoenberg, On asymptotic distributions of arithmetical functions, Transactions of the American Mathematical Society, Vol. 39, No. 2 (1936), pp. 315-330.
MATHEMATICA
A056170[n_] := Count[FactorInteger[n], {_, k_ /; k > 1}]; Select[Range[200], OddQ[A056170[#]] &] (* after Jean-François Alcover at A056170 *)
PROG
(PARI) \\ here b(n) is A056170(n)
b(n)={my(f=factor(n)[, 2]); sum(i=1, #f, f[i]>1)}
{ select(k->b(k)%2, [1..200]) } \\ Andrew Howroyd, Sep 28 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Sep 28 2019
STATUS
approved