One of the best OEIS sequences in terms of user comments is surely A000027 (the positive integers, sure to be filled with silly 'explanations'). My favorites:

One of the best OEIS sequences in terms of user comments is surely A000027 (the positive integers, sure to be filled with silly 'explanations'). My favorites: a(n) is also the number of permutations simultaneously avoiding 213, 231 and 321 in the classical sense which can be realized as labels on an increasing strict binary tree with 2n-1 nodes. See A245904 for more information on increasing strict binary trees. - Manda Riehl Number of n-digit numbers the binary expansion of which contains one run of 1's. - Vladimir Shevelev