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A086816 Smaller member of a twin prime pair with a triangular sum. 1
17, 59, 137, 149, 1277, 1619, 2729, 4127, 6359, 11717, 13397, 17489, 20807, 23027, 28307, 29669, 51869, 61379, 69827, 73847, 78539, 92567, 97499, 115769, 138569, 166667, 176609, 193379, 200927, 258317, 304979, 430007, 500909, 518759, 536189 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
It is easily shown that all terms end in 7 or 9.
LINKS
EXAMPLE
59 is a term because it is the smaller member of the twin prime pair (59,61) and 59 + 61 = 120 = 15*(15+1)/2.
MATHEMATICA
Transpose[Select[Partition[Prime[Range[45000]], 2, 1], #[[2]]-#[[1]]==2 && IntegerQ[(Sqrt[1+8Total[#]]-1)/2]&]][[1]] (* Harvey P. Dale, Dec 15 2011 *)
CROSSREFS
Sequence in context: A104165 A031391 A176783 * A243096 A221569 A179816
KEYWORD
nonn
AUTHOR
Jason Earls, Aug 06 2003
STATUS
approved

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Last modified May 30 14:34 EDT 2024. Contains 372968 sequences. (Running on oeis4.)