The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #13 Apr 20 2021 11:30:27
%S 2,3,4,5,10,11,23,27,29,34,38,41,46,53,55,57,62,76,77,83,89,91,93,106,
%T 113,118,123,129,131,133,136,143,145,159,161,173,177,179,185,191,201,
%U 203,205,206,212,213,218,226,232,233,235,239,251,259,267,281,291,293
%N Numbers k such that tau(k) = tau(2k+1).
%C If a term is a perfect square, then its square root must be in A001542. The first few such terms are the squares of 2, 2378, 93222358, 165326326037771920630... - _Ivan Neretin_, May 25 2016
%H Ivan Neretin, <a href="/A074821/b074821.txt">Table of n, a(n) for n = 1..10014</a>
%t Select[Range[300], DivisorSigma[0, #] == DivisorSigma[0, 2 # + 1] &] (* _Ivan Neretin_, May 25 2016 *)
%K nonn
%O 1,1
%A _Benoit Cloitre_, Sep 08 2002