OFFSET
1,1
COMMENTS
If one uses all 4^3=64 forms of this type but no parentheses, the sequence starts 4,9,15,13,15,14... In this case 4/4/4/4=1/4/4=1/16 is not an integer (association left-to-right), whereas with parenthesis one could write (4/4)/(4/4)=1, an integer, for example. The definition need clarification in this respect. [From R. J. Mathar, Jan 22 2009]
FORMULA
If k >3, a(2k-1)=30 and a(2k)=31. - Ken Levasseur, Oct 01 2008
EXAMPLE
You can form the numbers 1, 2, 3, 4 with 4 ones; hence the first term is 4.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Ken Levasseur, Sep 29 2008
STATUS
approved