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A015843 Numbers n such that phi(n) | sigma(n + 5). 6
1, 2, 6, 9, 10, 16, 18, 22, 28, 30, 33, 42, 64, 65, 71, 72, 82, 87, 90, 114, 130, 136, 156, 182, 198, 208, 215, 280, 294, 336, 380, 390, 403, 451, 616, 660, 683, 755, 777, 964, 990, 1168, 1260, 1267, 1330, 1342, 1348, 1480, 1638, 1744, 1953, 2025, 2074, 2088 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[3000], Divisible[DivisorSigma[1, 5 + #], EulerPhi[#]] &] (* David Nacin, Mar 03 2012 *)

PROG

(PARI) isok(n) = !(sigma(n+5) % eulerphi(n)); \\ Michel Marcus, Feb 05 2017

CROSSREFS

Sequence in context: A276937 A243373 A085304 * A109600 A071814 A066586

Adjacent sequences:  A015840 A015841 A015842 * A015844 A015845 A015846

KEYWORD

nonn

AUTHOR

Robert G. Wilson v

EXTENSIONS

a(1) = 1 added by Ivan Neretin, Feb 05 2017

STATUS

approved

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Last modified April 26 09:52 EDT 2019. Contains 322472 sequences. (Running on oeis4.)