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A166981 Superabundant numbers (A004394) that are highly composite (A002182). 7

%I

%S 1,2,4,6,12,24,36,48,60,120,180,240,360,720,840,1260,1680,2520,5040,

%T 10080,15120,25200,27720,55440,110880,166320,277200,332640,554400,

%U 665280,720720,1441440,2162160,3603600,4324320,7207200,8648640,10810800

%N Superabundant numbers (A004394) that are highly composite (A002182).

%C The intersection of superabundant and highly composite numbers has exactly 449 terms, the largest of which is 2^10 3^6 5^4 7^3 11^3 13^2 17^2 19^2 23^2 29 31 37...347.

%C The argument showing that this is a finite sequence seems to be given in A166735. - _N. J. A. Sloane_, Jan 04 2019

%C Pillai proved that this sequence is finite and asked for its number of terms (he used the term "highly abundant" for superabundant numbers). - _Amiram Eldar_, Jun 30 2019

%H T. D. Noe, <a href="/A166981/b166981.txt">Table of n, a(n) for n=1..449</a> (complete sequence)

%H S. Sivasankaranarayana Pillai, <a href="https://web.archive.org/web/20150912090449/http://www.calmathsoc.org/bulletin/article.php?ID=B.1943.35.20">Highly abundant numbers</a>, Bulletin of the Calcutta Mathematical Society, Vol. 35, No. 1 (1943), pp. 141-156.

%H S. Sivasankaranarayana Pillai, <a href="https://archive.org/details/in.ernet.dli.2015.282686/page/n825">On numbers analogous to highly composite numbers of Ramanujan</a>, Rajah Sir Annamalai Chettiar Commemoration Volume, ed. Dr. B. V. Narayanaswamy Naidu, Annamalai University, 1941, pp. 697-704.

%Y Cf. A166735 (SA numbers that are not HC numbers).

%K fini,full,nonn

%O 1,2

%A _T. D. Noe_, Oct 26 2009

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Last modified September 21 23:55 EDT 2019. Contains 327286 sequences. (Running on oeis4.)