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 A317089 Numbers whose prime factors span an initial interval of prime numbers and whose prime multiplicities span an initial interval of positive integers. 19
 2, 6, 12, 18, 30, 60, 90, 150, 180, 210, 300, 360, 420, 450, 540, 600, 630, 1050, 1260, 1350, 1470, 1500, 2100, 2250, 2310, 2520, 2940, 3150, 3780, 4200, 4410, 4620, 5880, 6300, 6930, 7350, 8820, 9450, 10500, 11550, 12600, 13230, 13860, 14700, 15750, 16170 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Andrew Howroyd, Table of n, a(n) for n = 1..300 EXAMPLE The sequence of rows of A296150 indexed by the terms of this sequence begins: (1), (21), (211), (221), (321), (3211), (3221), (3321), (32211), (4321), (33211), (322111), (43211). MATHEMATICA normalQ[m_]:=Union[m]==Range[Max[m]]; Select[Range[10000], And[normalQ[PrimePi/@FactorInteger[#][[All, 1]]], normalQ[FactorInteger[#][[All, 2]]]]&] PROG (PARI) ok(n)={my(f=factor(n), p=f[, 1], e=vecsort(f[, 2], , 8)); n > 1 && #p==primepi(p[#p]) && #e==e[#e]} \\ Andrew Howroyd, Aug 26 2018 CROSSREFS Cf. A001222, A007916, A055932, A056239, A124010, A133808, A242414, A296150. Cf. A317087, A317088, A317090, A317091, A317092. Sequence in context: A113274 A181660 A036913 * A117311 A125024 A178480 Adjacent sequences: A317086 A317087 A317088 * A317090 A317091 A317092 KEYWORD nonn AUTHOR Gus Wiseman, Jul 21 2018 STATUS approved

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Last modified March 2 21:08 EST 2024. Contains 370498 sequences. (Running on oeis4.)