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A067263 Numbers k such that sigma(k+1) = 5*phi(k). 2
2184, 6930, 7020, 7644, 17640, 18564, 23660, 25200, 27404, 71280, 83720, 120834, 129150, 179010, 189630, 191100, 198015, 224664, 228780, 273504, 285480, 302280, 304290, 322335, 328320, 335664, 437580, 443079, 449904, 451044, 462644, 478400, 483735, 619190, 627759 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..35.

MATHEMATICA

Select[Range[7*10^5], DivisorSigma[1, #+1] == 5*EulerPhi[#] &] (* Amiram Eldar, Apr 24 2022 *)

CROSSREFS

Cf. A000010, A000203, A067260, A067261, A067262.

Sequence in context: A343777 A250628 A234733 * A206057 A130173 A130170

Adjacent sequences:  A067260 A067261 A067262 * A067264 A067265 A067266

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Feb 21 2002

EXTENSIONS

More terms from Amiram Eldar, Apr 24 2022

STATUS

approved

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Last modified August 18 13:09 EDT 2022. Contains 356212 sequences. (Running on oeis4.)