p[x_,t_]:=1-Erf[x/Sqrt[4*t]]
pa[x_,t_]:=1NIntegrate-+HypergeometricPFQ{},,,-*p[x,s],{s,0,Infinity},MinRecursion4,AccuracyGoal60,PrecisionGoal4,WorkingPrecision150
1/4
t
HypergeometricPFQ{},,,-
1
2
3
4
4
s
256t
Gamma
3
4
sHypergeometricPFQ{},,,-
3
4
5
4
4
s
256t
π
1/4
t
2
s
5
4
3
2
4
s
256t
2
t
Gamma1
4
-
1
4
s
500*Pi*(4^4)t
Plot[{Log[10,1-pa[0.1,10^t]]},{t,-3,8},PlotRangeAll,AxesLabel{Log[t],Log[1-P_0.5[x,t]]}]