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A067246 Numbers n such that phi(n) divides sigma(n+1) + sigma(n). 1
1, 2, 6, 8, 11, 14, 22, 30, 70, 86, 102, 116, 130, 140, 154, 186, 238, 286, 390, 406, 422, 454, 459, 646, 830, 869, 1015, 1070, 1120, 1518, 1528, 1710, 1742, 1870, 2670, 2871, 3586, 3654, 4394, 5070, 5214, 6102, 6446, 6692, 7295, 7943, 8339, 9204, 10664 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..218 (* All terms up to 5 million *)

MATHEMATICA

Select[Range[11000], Divisible[DivisorSigma[1, #]+DivisorSigma[1, #+1], EulerPhi[ #]]&] (* Harvey P. Dale, Jul 16 2018 *)

CROSSREFS

Cf. A000010, A000203.

Sequence in context: A285971 A079418 A298170 * A184420 A136496 A183173

Adjacent sequences:  A067243 A067244 A067245 * A067247 A067248 A067249

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Feb 20 2002

EXTENSIONS

First two terms prepended by Harvey P. Dale, Jul 16 2018

STATUS

approved

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Last modified December 15 14:37 EST 2019. Contains 329999 sequences. (Running on oeis4.)