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%I #11 Apr 29 2017 17:16:06
%S 1,316,333,549,844,963,981,1052,1233,1251,1304,1341,1359,1474,1629,
%T 1688,1737,1738,1996,2061,2144,2216,2421,2528,2547,2763,2979,3033,
%U 3082,3123,3141,3148,3231,3244,3283,3303,3411,3573,3634,3871,3879,3897,3988,4113
%N a(n) is here if it is not a prime number and it is an integer square root of an entry taken from A115557.
%H Giovanni Resta, <a href="/A115559/b115559.txt">Table of n, a(n) for n = 1..10000</a>
%F The commutator [sigma, tau] is zero and a(n) is the square root of solutions. Moreover this square root is a nonprime number.
%o (PARI) isok(n)= !isprime(n) && (sigma(numdiv(n^2)) == numdiv(sigma(n^2))); \\ _Michel Marcus_, Dec 20 2013
%Y Cf. A000005, A000203, A076360, A076361, A062068, A062069, A115557, A115559, A115560.
%K nonn
%O 1,2
%A _Labos Elemer_, Jan 25 2006
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