A067246 - OEIS

%I #17 Jul 23 2023 01:50:04

%S 1,2,6,8,11,14,22,30,70,86,102,116,130,140,154,186,238,286,390,406,

%T 422,454,459,646,830,869,1015,1070,1120,1518,1528,1710,1742,1870,2670,

%U 2871,3586,3654,4394,5070,5214,6102,6446,6692,7295,7943,8339,9204,10664

%N Numbers k such that phi(k) divides sigma(k+1) + sigma(k).

%H Harvey P. Dale, <a href="/A067246/b067246.txt">Table of n, a(n) for n = 1..218</a> (all terms up to 5 million)

%t Select[Range[11000],Divisible[DivisorSigma[1,#]+DivisorSigma[1,#+1], EulerPhi[ #]]&] (* _Harvey P. Dale_, Jul 16 2018 *)

%Y Cf. A000010, A000203.

%K easy,nonn

%O 1,2

%A _Benoit Cloitre_, Feb 20 2002

%E First two terms prepended by _Harvey P. Dale_, Jul 16 2018