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A092000
Numbers that can be expressed as the difference of the squares of primes in exactly four distinct ways.
21
240, 792, 912, 1248, 2040, 2280, 2760, 3528, 3720, 3960, 4080, 4440, 4680, 4872, 5160, 5520, 5880, 6600, 6720, 6960, 7080, 8520, 8568, 8760, 9072, 9120, 9672, 9912, 10248, 10440, 11088, 11592, 11832, 11880, 12408, 12480, 12720, 13200, 13560
OFFSET
1,1
EXAMPLE
240 = 17^2-7^2 = 19^2-11^2 = 23^2-17^2 = 61^2-59^2
CROSSREFS
KEYWORD
nonn
AUTHOR
Ray Chandler, Feb 22 2004
STATUS
approved