Question

1,3,4,9,10,12,13 pls solve the pattern

Answer 1

I think the next two digits are 18 and 19 then the difference between 1 and 3 is 1 then the difference between 4 and 9 is 5 then we go upper then difference between 10 and 12 is 1 so the series of difference is 1-5-1-5.....