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 A073245 Sum of all cubefree numbers with the same squarefree kernel as the n-th squarefree number. 2
 1, 6, 12, 30, 72, 56, 180, 132, 182, 336, 360, 306, 380, 672, 792, 552, 1092, 870, 2160, 992, 1584, 1836, 1680, 1406, 2280, 2184, 1722, 4032, 1892, 3312, 2256, 3672, 2862, 3960, 4560, 5220, 3540, 3782, 5952, 5460, 9504, 4556, 6624, 10080, 5112, 5402 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A062822(n)*A005117(n). Sum_{n>=1} 1/a(n) = A306633. - Amiram Eldar, Oct 14 2020 a(n) = A064987(A005117(n)). - Michel Marcus, Oct 18 2020 EXAMPLE 14 is the 10th squarefree number: A005117(10)=14=2*7, the cubefree numbers with squarefree kernel =14 are 14, 28=2*2*7, 98=2*7*7 and 196=2*2*7*7; therefore a(10)=14+28+98+196=336; a(10)=A062822(10)*A005117(10)=24*14=336. MATHEMATICA Map[# * DivisorSigma[1, #] &, Select[Range[200], SquareFreeQ]] (* Amiram Eldar, Oct 14 2020 *) PROG (PARI) apply(x->(x*sigma(x)), select(issquarefree, [1..100])) \\ Michel Marcus, Oct 18 2020 CROSSREFS Cf. A004709, A005117, A007947, A062822, A064987, A072048, A306633. Sequence in context: A236539 A122211 A015801 * A119626 A152522 A096356 Adjacent sequences: A073242 A073243 A073244 * A073246 A073247 A073248 KEYWORD nonn AUTHOR Reinhard Zumkeller, Jul 21 2002 STATUS approved

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Last modified March 25 17:06 EDT 2023. Contains 361528 sequences. (Running on oeis4.)