A218404 Numbers k for which sigma(k)/k - 1/4 is an integer.

40, 224, 360, 2016, 174592, 524160, 1571328, 492101632, 4428914688, 83350779494400, 2163091537152000, 2251247910912000, 2931032952207360, 7487050986455040, 155086041146982400, 369127262068899840, 12682035945406464000, 12848564519239680000

Offset

1,1

Comments

a(10) > 10^11. - Donovan Johnson, Oct 31 2012

a(10) > 10^12. - Giovanni Resta, Nov 04 2012

Note that there are no terms here with abundancy 5/4 (k=1). - Michel Marcus, Jun 26 2013

Links

Table of n, a(n) for n=1..18.

Crossrefs

Cf. A159907, A218405.

Sequence in context: A181637 A111176 A072108 * A235010 A235290 A074360

Adjacent sequences: A218401 A218402 A218403 * A218405 A218406 A218407

Keyword

nonn

Author

Zdenek Cervenka, Oct 28 2012

Extensions

a(8)-a(9) from Donovan Johnson, Oct 31 2012

More terms from Michel Marcus, Jun 26 2013

Status

approved