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 A098424 Number of prime triples (p,q,r) <= n with p
 0, 0, 0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 11 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,7 COMMENTS Convention: a prime triple is <= n iff its smallest member is <= n; a(n) <= A098428(n). LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 Eric Weisstein's World of Mathematics, Prime Triplet EXAMPLE a(15) = #{(5,7,11),(7,11,13),(11,13,17),(13,17,19)} = 4. MATHEMATICA With[{pts=Select[Partition[Prime[Range[1200]], 3, 1], Last[#]-First[#] == 6&]}, Table[Count[pts, _?(First[#]<=n&)], {n, 110}]] (* Harvey P. Dale, Nov 09 2011 *) PROG (Haskell) a098424 n = length [(p, q, r) | p <- takeWhile (<= n) a000040_list,             let r = p + 6, a010051 r == 1, q <- [p+1..r-1], a010051 q == 1] -- Reinhard Zumkeller, Nov 15 2011 CROSSREFS Cf. A007529, A098414, A098415, A071538. Cf. A010051, A000040. Sequence in context: A024542 A209082 A257684 * A098428 A023193 A096605 Adjacent sequences:  A098421 A098422 A098423 * A098425 A098426 A098427 KEYWORD nonn AUTHOR Reinhard Zumkeller, Sep 07 2004 STATUS approved

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Last modified May 17 23:07 EDT 2022. Contains 353779 sequences. (Running on oeis4.)