OFFSET
1,2
COMMENTS
FORMULA
a(n) = -1 + position of the n-th positive integer in the sequence A131389=(0,1,2,-1,3,4,-2,-3,6,-4,5,...)
EXAMPLE
The 5th positive integer to occur in A131391 is 6, which occurs in position 9, so that a(5) = 9 - 1 = 8.
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jul 06 2007
STATUS
approved