I am specially interested in number theory, in particular very large numbers.
89 Least prime of the form $38^n+31$ Dec 7 '13
38 Why do I get one extra wrong solution? Jan 19
36 Making 400k random choices from 400k samples seems to always end up with 63% distinct choices, why? Jul 21 '14
26 Are there $n$ groups of order $n$ for some $n>1$? Nov 26 '15
21 What is the smallest prime of the form $n^n+8$? May 30 '15
17 Draw cards repeatedly, until we find the ace of spades. Probability that we draw between 20 and 30 cards? Jan 17
15 A prime of the form $38111111\ldots$ Jan 2 '14