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 A306864 Lexicographically earliest sequence of distinct positive terms such that among the prime divisors of the product of two consecutive terms there are at least 4 runs of consecutive prime numbers. 2
 1, 1870, 2, 935, 4, 1045, 8, 1235, 10, 187, 20, 209, 40, 247, 14, 299, 21, 377, 28, 391, 22, 85, 44, 95, 26, 115, 34, 55, 38, 65, 46, 91, 57, 182, 19, 110, 17, 220, 23, 130, 29, 170, 11, 190, 13, 230, 31, 238, 37, 260, 41, 266, 39, 133, 52, 145, 68, 155, 76 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This sequence is a variant of A285487. This sequence is likely a permutation of the natural numbers. LINKS Rémy Sigrist, Table of n, a(n) for n = 1..25000 Rémy Sigrist, Scatterplot of the first 25000 terms Rémy Sigrist, PARI program for A306864 FORMULA A287170(a(n) * a(n+1)) >= 4. EXAMPLE The first terms, alongside the corresponding runs, are:    n   a(n)  runs in a(n)*a(n+1)   ---  ----  -------------------     1     1  2, 5, 11, 17     2  1870  2, 5, 11, 17     3     2  2, 5, 11, 17     4   935  2, 5, 11, 17     5     4  2, 5, 11, 19     6  1045  2, 5, 11, 19     7     8  2, 5, 13, 19     8  1235  2, 5, 13, 19     9    10  2, 5, 11, 17    10   187  2, 5, 11, 17    11    20  2, 5, 11, 19    12   209  2, 5, 11, 19   ...    32    91  3, 7, 13, 19    33    57  2-3, 7, 13, 19    34   182  2, 7, 13, 19   ...   662  1222  2, 7, 13, 47   663   448  2, 7, 17, 73   664  1241  2-3, 7-11, 17, 73   665   462  2-3, 7-11, 29, 43   666  1247  3, 17, 29, 43   ... PROG (PARI) See Links section. CROSSREFS Cf. A287170, A285487. Sequence in context: A054816 A052168 A237152 * A306877 A073495 A073489 Adjacent sequences:  A306861 A306862 A306863 * A306865 A306866 A306867 KEYWORD nonn,look AUTHOR Rémy Sigrist, Mar 14 2019 STATUS approved

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Last modified January 19 03:54 EST 2020. Contains 331031 sequences. (Running on oeis4.)