▁▁ ▁Since ▁the ▁log arith mic ▁integral ▁is ▁defined ▁by ▁ ▁we ▁have ▁ ▁thus ▁eas ing ▁calculation ▁for ▁positive ▁integers . ▁ ▁Also , ▁since ▁the ▁exponential ▁integral ▁function ▁satisfies ▁the ▁equation ▁ ▁the ▁only ▁positive ▁zero ▁of ▁the ▁exponential ▁integral ▁occurs ▁at ▁the ▁natural ▁log arith m ▁of ▁the ▁Ram an uj an – S old ner ▁constant , ▁whose ▁value ▁is ▁approximately ▁l n ( μ ) ▁ ≈ ▁ 0 . 3 7 2 5 0 7 4 1 0 7 8 1 3 6 6 6 3 4 4 6 1 9 9 1 8 6 6 … ▁ ▁External ▁links ▁ ▁Category : Math emat ical ▁constants ▁Category : S rin iv asa ▁Ram an uj an <0x0A> </s> ▁The ▁Van ished ▁() ▁is ▁a ▁ 2 0 1 8 ▁South ▁Korean ▁psych ological ▁thr iller ▁film ▁directed ▁by ▁Lee ▁Ch ang - he e , ▁st arring ▁Kim ▁Sang - ky ung , ▁Kim ▁K ang - wo o ▁and ▁Kim ▁He e - ae . ▁It ▁is ▁a ▁re make ▁of ▁the ▁ 2 0 1 2 ▁Spanish ▁film ▁The ▁Body , ▁directed ▁by ▁Ori ol ▁Paulo . ▁ ▁Plot ▁Y oon ▁Se ol - he e , ▁a ▁famous ▁married ▁cha ebol , ▁recently ▁died . ▁On ▁the ▁day ▁of ▁her ▁fun eral , ▁her ▁body ▁was ▁myster iously ▁st olen . ▁Det ect ive ▁Jung - s ik ▁investig ated ▁the ▁case ▁and ▁requested ▁the ▁presence ▁of ▁Se ol - he e '