A175589 Numbers k that divide the sum of digits of 21^k.

1, 3, 6, 9, 12, 18, 57, 84, 87, 102, 117, 216, 234, 288, 360, 468, 477, 681, 741, 798, 987, 1029, 1161, 1245, 1251, 1266, 1449, 1458, 1500, 1677, 2214, 2232, 2703, 2880, 3090, 3117, 3333, 3345, 3351, 3789, 4176, 4512, 4779, 4932, 4980, 5763, 6213, 6846, 6903, 6918, 8097, 8712, 9285, 10404, 11085, 11274, 11532, 11922, 12369, 12378, 14871, 16710

Offset: 1

Author

T. D. Noe and N. J. A. Sloane, Dec 03 2010

Keywords

• nonn
• base

Comments

No more terms < 10^6 using the same method used for A175525. - Donovan Johnson, Dec 08 2010

Programs

Mathematica

Select[Range[10000], Mod[Total[IntegerDigits[21^#]], #] == 0 &]

Extensions

a(54)-a(62) from Donovan Johnson, Dec 08 2010