OFFSET
1,6
EXAMPLE
n=10: the squarefree kernels are {1, 10, 15, 30, 210, 42, 210, 30, 15, 10, 1}. The maximal value is 210 and the central one is 42. Thus a(10) = 210 - 42 = 168.
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved