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A068077 Numbers n such that sigma(n)+sigma(n+1)=4n. 2
1, 38184, 458010, 776112, 65676408, 1488668112, 4414086384, 28645019964, 46696401675, 65466785748, 70619381496, 176151711072 (list; graph; refs; listen; history; text; internal format)
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

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Last modified September 16 06:18 EDT 2021. Contains 347469 sequences. (Running on oeis4.)