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A067806 Numbers n such that sigma(n+1)+sigma(n)=3n. 3
10, 34, 136, 169, 2402, 5329, 21004, 41164, 54722, 1060802, 5026562, 10800112, 11108164, 14366402, 87026656, 102944992, 10499710072, 107000850688, 220200311872, 924354816004 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

Table of n, a(n) for n=1..20.

MATHEMATICA

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

CROSSREFS

Cf. A068077, A068078.

Sequence in context: A166066 A232583 A068078 * A001446 A264671 A232902

Adjacent sequences:  A067803 A067804 A067805 * A067807 A067808 A067809

KEYWORD

more,nonn

AUTHOR

Benoit Cloitre, Feb 07 2002

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

STATUS

approved

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Last modified February 24 03:22 EST 2020. Contains 332195 sequences. (Running on oeis4.)