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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 Harvey P. Dale, Table of n, a(n) for n = 0..300 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 Cf. A000217, A001359. Sequence in context: A104165 A031391 A176783 * A243096 A221569 A179816 Adjacent sequences:  A086813 A086814 A086815 * A086817 A086818 A086819 KEYWORD nonn AUTHOR Jason Earls, Aug 06 2003 STATUS approved

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Last modified December 4 04:49 EST 2021. Contains 349469 sequences. (Running on oeis4.)