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A222963
a(n) = (p-3)*(p+3)/4 where p is the n-th prime.
1
0, 4, 10, 28, 40, 70, 88, 130, 208, 238, 340, 418, 460, 550, 700, 868, 928, 1120, 1258, 1330, 1558, 1720, 1978, 2350, 2548, 2650, 2860, 2968, 3190, 4030, 4288, 4690, 4828, 5548, 5698, 6160, 6640, 6970, 7480, 8008, 8188
OFFSET
2,2
COMMENTS
Old name was: Numbers n such that sqrt(4*n+9) is prime.
LINKS
FORMULA
4*a(n)+9 = A001248(n).
a(n) = A166011(n)/2. - Michel Marcus, Apr 22 2016
MATHEMATICA
Select[Range[0, 10000], PrimeQ[Sqrt[4 # + 9]]&]
PROG
(Magma) [(p^2-9)/4: p in PrimesInInterval(3, 200)];
CROSSREFS
Subsequence of A028552.
Sequence in context: A186278 A367437 A367124 * A333172 A257028 A174938
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 05 2013
STATUS
approved