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A080766
A unitary phi reciprocal amicable number: consider two different numbers a, b which satisfy the following equation for some integer k: uphi(a)=uphi(b)=1/k*a*b/(a-b); or equivalently, 1/uphi(a)=1/uphi(b)=k*(-1/a+1/b); sequence gives a numbers.
2
2, 6, 14, 21, 240, 240, 242, 5520, 5566, 6578, 10881, 13056, 14880, 15444, 46200, 47908, 57600, 60480, 65280, 65292, 91392, 152320, 169728, 239540, 285696, 399168, 665280, 702000, 941625, 1405404
OFFSET
0,1
COMMENTS
Here uphi(n)=A047994(n) is the unitary totient function: if n = Product p_i^e_i, uphi(n) = Product (p_i^e_i - 1).
CROSSREFS
KEYWORD
nonn
EXTENSIONS
Kohmoto found 2nd, 6th, 13th, 25th terms. Dean Hickerson calculated the other terms.
STATUS
approved