Research

29 perm from 1 to n cons sum prime
52 perm st any four indices no arith prog
90? binary length n more than any other alph size
114? frac of s2(n+t) >= s2(n)
137? sum C(n,j) (-1)^C(j,d) = 0
161 a_n+1 = b mod a_n pierce
205 num of sum C(c,i)^-1 divisible by prime^2
214 bool mat worst case no. distinct powers
215/228? average period of binary word
216 n^2 only 0 and 1 in base-7
245? lcm ordp(2) asymptotic lower bound
261 irrational number base-b easy base-b' hard
298 {0}, {1}  union, intersect, complement, set-sum, set-prod
299? x = sum of 1/a_i choose a_i greedily Lebesgue measure
311 Presburger + Cube-detector
312 Presburger + Perfect-Power-detector
313 Presburger + omegas
330 powers of 2 expressible in base -3 using 0 and 1 only