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 A073495 Numbers having exactly three prime gaps in their factorization. 6
 1870, 2090, 2470, 2530, 2990, 3190, 3410, 3458, 3740, 3770, 3910, 4030, 4070, 4180, 4186, 4510, 4730, 4810, 4930, 4940, 5060, 5170, 5187, 5270, 5278, 5330, 5474, 5510, 5590, 5642, 5830, 5890, 5980, 6110, 6279, 6290, 6380, 6490, 6710, 6734, 6820, 6890 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA A073490(a(n)) = 3. EXAMPLE 1870 is a term, as 1870 = 2*5*11*17 with three gaps: between 2 and 5, between 5 and 11 and between 11 and 17. MATHEMATICA q[n_] := SequenceCount[FactorInteger[n][[;; , 1]], {p1_, p2_} /; p2 != NextPrime[p1], Overlaps -> True] == 3; Select[Range[7000], q] (* Amiram Eldar, Apr 10 2021*) PROG (Haskell) a073495 n = a073495_list !! (n-1) a073495_list = filter ((== 3) . a073490) [1..] -- Reinhard Zumkeller, Dec 20 2013 CROSSREFS Cf. A005117, A073490, A073492, A073493, A073494, A073489. Sequence in context: A237152 A306864 A306877 * A073489 A353552 A232040 Adjacent sequences:  A073492 A073493 A073494 * A073496 A073497 A073498 KEYWORD nonn AUTHOR Reinhard Zumkeller, Aug 03 2002 STATUS approved

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Last modified August 7 23:50 EDT 2022. Contains 355995 sequences. (Running on oeis4.)