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A306621 Highly abundant numbers that are powerful. 0
1, 4, 8, 16, 36, 72, 108, 144, 216, 288, 1800, 3600, 7200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Alaoglu and Erdős proved that 7200 is the last term.

Intersection of A001694 and A002093.

LINKS

Table of n, a(n) for n=1..13.

Leonidas Alaoglu and Paul Erdős, On highly composite and similar numbers, Transactions of the American Mathematical Society, Vol. 56, No. 3 (1944), pp. 448-469.

MATHEMATICA

seq={1}; sm = 0; Do[s = DivisorSigma[1, n]; If[s>sm, sm = s; If[ Min @  FactorInteger[n][[;; , 2]] > 1, AppendTo[seq, n]]], {n, 2, 72000}]; seq

CROSSREFS

Cf. A001694, A002093.

Sequence in context: A214035 A040014 A141069 * A144687 A278377 A065605

Adjacent sequences:  A306618 A306619 A306620 * A306622 A306623 A306624

KEYWORD

nonn,fini,full

AUTHOR

Amiram Eldar, Mar 01 2019

STATUS

approved

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Last modified October 20 03:04 EDT 2021. Contains 348099 sequences. (Running on oeis4.)