A048251 a(n) is the smallest number whose sum of divisors is 6^n.

1, 5, 22, 102, 510, 3210, 17490, 112890, 600270, 3466470, 20205570, 118879530, 697118730, 3949737330, 24217298490, 143487592710, 841422307110, 4973562896610, 29520886859310, 180254162529210, 1052751138726210, 6301225298627490, 37854941354933010, 224270177470178070

Offset: 0

Author

Labos Elemer

Keywords

• nonn

Comments

Terms of this sequence are products of distinct terms in A005105. - Ray Chandler, Sep 01 2010

Examples

			sigma(k) = 1296 = 6^4 for each k in {510, 642, 710, 742, 782, 795, 862, 935, 1177, 1207, 1219}; the smallest of these is a(4)=510.
		

Links

• Ray Chandler, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A006532, A020477, A019422, A019423, A018427, A048252-A048256.

Programs

PARI

a(n) = {my(k=1); while (sigma(k) != 6^n, k++); k;} \\ Michel Marcus, May 14 2018

Formula

a(n) = Min{k : A000203(k) = 6^n}.

Extensions

a(9)-a(14) from Donovan Johnson, Sep 02 2008

a(15)-a(24) from Walter Kehowski, Aug 22 2010

Edited and extended by Ray Chandler, Sep 01 2010

Error in sequence corrected by N. J. A. Sloane, Oct 04 2010