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A171569
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Triangular numbers T such that T-2 is a prime.
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1
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15, 21, 45, 55, 91, 105, 153, 231, 253, 351, 435, 465, 595, 703, 741, 861, 1035, 1225, 1431, 1485, 1711, 1891, 1953, 2145, 2701, 3003, 3081, 3321, 3741, 4005, 4095, 4465, 4753, 5565, 5671, 6555, 7021, 7875, 8515, 9045, 10011, 10153, 10731, 11175, 11781
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OFFSET
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1,1
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LINKS
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EXAMPLE
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15-2 = 13, 21-2 = 19, 45-2 = 43, ...
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MATHEMATICA
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Select[s=0; Table[n*(n+1)/2, {n, 6!}], PrimeQ[ #-2]&]
Select[Accumulate[Range[200]], PrimeQ[#-2]&] (* Harvey P. Dale, Apr 09 2018 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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