Values of theta(x) for x from 10^16 up to 1^18

 x                         Theta

1e16 9.999999887717104034899398453038441984901e15
2e16 1.999999986685955970777723838825521315536e16
3e16 2.999999983381789823047083407156472896572e16
4e16 3.999999979999025519296241800888968236027e16
5e16 4.999999974488184855538746801968846633194e16
6e16 5.999999979892928726107204042174293327511e16
7e16 6.999999969634092942607731129183064160421e16
8e16 7.999999977477416391568535495476374278724e16
9e16 8.999999966457952550394494257762530960179e16

1e17 9.999999970658237245237106386726739765820e16
2e17 1.999999995927881990126022091126378161513e17
3e17 2.999999994433788779693686895323103220670e17
4e17 3.999999992321600669206683921987929031319e17
5e17 4.999999992617602954130240747008428765472e17
6e17 5.999999991993445568258846918045887824525e17
7e17 6.999999992899441182068062443271696550301e17
8e17 7.999999993573272993127866212628461968629e17
9e17 8.999999989644217057320686945831984400220e17

1e18 9.999999991441156345121090679953180049327e17