Apocalyptic Numbers

Note 1 : Write a Program in any Language

Note 2 : If you have any doubt ask in comment

Note 3 : Winners will be decided on code posting time and on my likes if code will pass all test cases.

Apocalyptic Numbers:

In this challenge, you have to establish if a number is apocalyptic. A positive integer n greater than 0 is apocalyptic when 2 elevated to n contains one or more occurrences of 666 into it.

Given an integer n, implement a function that returns:

"Safe" if n is not apocalyptic.
"Single" if into 2^n there's a single occurence of 666.
"Double" if into 2^n there are two occurences of 666.
"Triple" if into 2^n there are three occurences of 666.

Example:

Input - 66
// 2^66 = 73786976294838206464
Output - Safe

Input - 157
// 2^157 =
182687704666362864775460604089535377456991567872
Output - Single

Input - 220
// 2^220 =
168499666669691498716668844293872691710232152640 ...
Output - Double

Input - 931
// 2^931 =
// 1815206187106668777829666135436890332191479738353753001777065257954029122510259245050254290156440857653562895251700406555730694879815558725330603736697259064676478076718090666 ...
Output - Triple

Notes:

Any given n will be a positive integer in the range of 1 to 1000.
Occurrences have to be unique, you can't use digits that have already been matched again (see example #3, there are five adjacent 6 (66666), but only a possible match).

Coding Challenge for U 4 - Apocalyptic Numbers