OFFSET
1,1
FORMULA
Product_{k=n(n-1)/2 + 1..n(n+1)/2} a(k) = A290042(n) for n > 0.
EXAMPLE
A290042(2) = 15 = 3*5, so 3 and 5 are members.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Sondow, Aug 20 2017
STATUS
approved