H&c solid concrete stain. Or you could apply a masonry primer such as loxon from SW and two coats of a quality acrylic latex paint, but the concrete stain eliminates the step of priming. The stain can be found at SW.
Well said HPNY. Also, make sure to gently clean or wire brush any loose or peeling paint that's on there now. I say gently because block foundations can literally crumble away from a strong pressure wash or aggressive scraping.
You might consider stuccoing it instead. You can color it and that will give you a better looking surface than the concrete block, and you have enough of it exposed that I think that's a better aesthetic option with much lower maintenance.