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 A300572 Numbers k such that k and the sum of the divisors of k have the same prime signature. 2
 1, 2, 12, 52, 75, 90, 98, 150, 338, 528, 560, 722, 867, 912, 1452, 1456, 1525, 1734, 1922, 2064, 2340, 2890, 3050, 3120, 3216, 3698, 4144, 4950, 5043, 6348, 6516, 6804, 7350, 7824, 8176, 8880, 9024, 9920, 10086, 10128, 10304, 10443, 10658, 11340, 11858, 13584 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS 2 is the only prime. - Michel Marcus, Mar 10 2018 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..3000 FORMULA { k | A046523(k) = A046523(A000203(k)) }. MAPLE s:= n-> sort(map(i-> i[2], ifactors(n)[2])): a:= proc(n) option remember; local k; for k from 1+       a(n-1) while s(k)<>s(numtheory[sigma](k)) do od; k     end: a(0):=0: seq(a(n), n=1..60); PROG (PARI) isok(k) = vecsort(factor(k)[, 2]) == vecsort(factor(sigma(k))[, 2]); \\ Michel Marcus, Mar 10 2018 CROSSREFS Cf. A000203, A008578, A046523, A300216, A300573. Sequence in context: A057547 A216648 A043007 * A176580 A179259 A261474 Adjacent sequences:  A300569 A300570 A300571 * A300573 A300574 A300575 KEYWORD nonn AUTHOR Alois P. Heinz, Mar 08 2018 STATUS approved

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Last modified September 17 12:00 EDT 2021. Contains 347477 sequences. (Running on oeis4.)