A201558 - OEIS

%I #18 Apr 01 2015 17:31:48

%S 0,0,0,0,0,0,0,0,0,0,2,4,2,1,1,2,4,1,2,3,7,7,7,1,4,7

%N Number of GA1 numbers A197638 with n >= 3 prime factors counted with multiplicity.

%C The number of GA1 numbers with one (resp., two) prime factors is zero (resp., infinity).

%C GA1 numbers with at least three prime factors are called "proper" - see A201557.

%C For a(n), see Section 6.2 of "On SA, CA, and GA numbers", and below "kmax" in "Table of proper GA1 numbers up to 10^60".

%H G. Caveney, J.-L. Nicolas, and J. Sondow, <a href="http://www.integers-ejcnt.org/l33/l33.pdf">Robin's theorem, primes, and a new elementary reformulation of the Riemann Hypothesis</a>, Integers 11 (2011), article A33.

%H G. Caveney, J.-L. Nicolas and J. Sondow, <a href="http://arxiv.org/abs/1112.6010">On SA, CA, and GA numbers</a>, Ramanujan J., 29 (2012), 359-384 and arXiv:1112.6010.

%H J.-L. Nicolas, <a href="http://math.univ-lyon1.fr/~nicolas/GAnumbers.html">Computation of GA1 numbers</a>, 2011.

%H J.-L. Nicolas, <a href="http://math.univ-lyon1.fr/~nicolas/GA160">Table of proper GA1 numbers up to 10^60</a>, 2011.

%e 183783600 = 2^4 * 3^3 * 5^2 * 7 * 11 * 13 * 17 is the first of the a(13) = 2 GA1 numbers with 4 + 3 + 2 + 1 + 1 + 1 + 1 = 13 prime factors.

%p See "Computation of GA1 numbers".

%Y Cf. A067698, A197638, A197639, A201557.

%K nonn

%O 3,11

%A Geoffrey Caveney, Jean-Louis Nicolas, and _Jonathan Sondow_, Dec 03 2011