A067806 Numbers n such that sigma(n+1)+sigma(n)=3n.

10, 34, 136, 169, 2402, 5329, 21004, 41164, 54722, 1060802, 5026562, 10800112, 11108164, 14366402, 87026656, 102944992, 10499710072, 107000850688, 220200311872, 924354816004

Offset: 1

Author

Benoit Cloitre, Feb 07 2002

Keywords

• more
• nonn

Comments

a(21) > 10^13. - Giovanni Resta, Jul 11 2013

Crossrefs

Cf. A068077, A068078.

Programs

Mathematica

For[n=1, True, n++, If[DivisorSigma[1, n]+DivisorSigma[1, n+1]==3n, Print[n]]]

Extensions

Edited by Dean Hickerson, Feb 16 2002

a(17) from Donovan Johnson, Jan 31 2009

a(18)-a(20) from Giovanni Resta, Jul 11 2013