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 A303283 Squarefree numbers whose prime indices have no common divisor other than 1 but are not pairwise coprime. 9
 42, 78, 105, 114, 130, 174, 182, 195, 210, 222, 230, 231, 258, 266, 285, 318, 345, 357, 366, 370, 390, 406, 426, 429, 435, 455, 462, 470, 474, 483, 494, 518, 534, 546, 555, 570, 598, 602, 606, 610, 627, 638, 642, 645, 651, 663, 665, 678, 690, 705, 714, 715 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A prime index of n is a number m such that prime(m) divides n. Two or more numbers are coprime if no pair of them has a common divisor other than 1. The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). LINKS EXAMPLE The sequence of strict integer partitions whose Heinz numbers belong to this sequence begins (4,2,1), (6,2,1), (4,3,2), (8,2,1), (6,3,1), (10,2,1), (6,4,1), (6,3,2), (4,3,2,1), (12,2,1), (9,3,1), (5,4,2), (14,2,1), (8,4,1), (8,3,2), (16,2,1), (9,3,2), (7,4,2), (18,2,1), (12,3,1), (6,3,2,1). MATHEMATICA primeMS[n_]:=If[n===1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]]; Select[Range[400], SquareFreeQ[#]&&!CoprimeQ@@primeMS[#]&&GCD@@primeMS[#]===1&] CROSSREFS Cf. A000837, A001222, A018783, A051424, A056239, A078374, A168532, A289508, A289509, A296150, A298748, A300486, A302569, A302696, A302796, A303138, A303139, A303140, A303282. Sequence in context: A039525 A072326 A068700 * A135850 A250381 A153644 Adjacent sequences:  A303280 A303281 A303282 * A303284 A303285 A303286 KEYWORD nonn AUTHOR Gus Wiseman, Apr 20 2018 STATUS approved

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Last modified August 6 15:33 EDT 2020. Contains 336252 sequences. (Running on oeis4.)