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A176681
Numbers k such that k^2 +-5 are primes.
6
6, 12, 36, 72, 78, 168, 198, 204, 342, 432, 456, 492, 534, 588, 594, 666, 726, 756, 786, 804, 996, 1014, 1212, 1218, 1248, 1254, 1266, 1314, 1344, 1476, 1512, 1554, 1806, 1812, 1902, 2088, 2298, 2322, 2364, 2616, 2634, 3066, 3072, 3162, 3432, 3444, 3852
OFFSET
1,1
LINKS
EXAMPLE
12 is in the sequence, because 12^2 + 5 = 149 and 12^2 - 5 = 139 are primes.
MATHEMATICA
Select[Range[8! ], PrimeQ[ #^2-5]&&PrimeQ[ #^2+5]&]
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved