1,1
Problem: find an upper estimate for a(n).
Cf. A159885 A006519 A007814 A000120
Sequence in context: A035050 A198790 A046819 * A089216 A102746 A123143
Adjacent sequences: A159942 A159943 A159944 * A159946 A159947 A159948
nonn
Vladimir Shevelev (shevelev(AT)bgu.ac.il), Apr 27 2009