A290592 Numbers x such that x = Sum_{j=1..k} d(j*x), for some k, where d(x) is the number of divisors of x.

1, 2, 9, 10, 26, 34, 46, 76, 121, 128, 136, 140, 174, 194, 226, 230, 232, 240, 268, 278, 296, 325, 362, 370, 432, 434, 438, 575, 598, 610, 620, 637, 694, 708, 718, 734, 735, 756, 796, 808, 842, 854, 860, 866, 898, 922, 925, 986, 1048, 1050, 1072, 1168, 1196, 1228

Offset: 1

Author

Paolo P. Lava, Aug 07 2017

Keywords

• nonn
• easy

Comments

Values of k for the listed items are 1, 1, 2, 2, 4, 5, 6, 7, 14, 9, 9, 7, 11, 19, 21, 13, 14, 8, 19, 25, 17, 18, 31, 19, 13, 21, 23, 29, 27, 28, 22, 31, 53, 26, 54, 55, 23, 17, 45, 38, 62, 36, 29, 63, 65, 66, 42, 40, 47, 21, 41, 44, 36, 65.

All squarefree terms > 1 are even. - Robert Israel, Aug 07 2017

Examples

			For 34 we have that d(34) + d(2*34) + d(3*34) + d(4*34) + d(5*34) = 4 + 6 + 8 + 8 + 8 = 34.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000005, A270713, A270389.

Programs

Maple

with(numtheory): P:=proc(n) local a,k; a:=0; k:=0; while a