A068077 Numbers n such that sigma(n)+sigma(n+1)=4n.

1, 38184, 458010, 776112, 65676408, 1488668112, 4414086384, 28645019964, 46696401675, 65466785748, 70619381496, 176151711072

Offset

1,2

Comments

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

Links

Table of n, a(n) for n=1..12.

Mathematica

For[n=1, True, n++, If[DivisorSigma[1, n]+DivisorSigma[1, n+1]==4n, Print[n]]]

Crossrefs

Cf. A067806, A068078.

Sequence in context: A187938 A235185 A172842 * A094427 A298427 A138400

Adjacent sequences: A068074 A068075 A068076 * A068078 A068079 A068080

Keyword

more,nonn

Author

Dean Hickerson, Feb 16 2002

Extensions

a(6)-a(8) from Donovan Johnson, Jan 31 2009

a(9)-a(12) from Giovanni Resta, Jul 11 2013

Status

approved