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%I #13 Jul 20 2019 18:51:48
%S 1,7,15,13,31,31,40,63,91,57,127,121,217,133,156,255,403,183,399,600,
%T 403,364,511,307,847,400,381,961,741,931,1023,553,1651,781,1281,1093,
%U 1767,871,2821,993,2340,2047,1729,2149,1767,3751,1464,1407,2667,2379
%N Sum of divisors of n-th perfect power.
%H Amiram Eldar, <a href="/A076401/b076401.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PerfectPower.html">Perfect Powers</a>.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/DivisorFunction.html">Divisor Function</a>.
%F a(n) = A000203(A001597(n)).
%p N:= 10^4: # to use all perfect powers <= N
%p L:= sort(convert({seq(seq(i^k, i=1..floor(N^(1/k))), k=2..ilog2(N))},list)):
%p map(numtheory:-sigma,L); # _Robert Israel_, Oct 02 2014
%o (PARI) lista(nn) = {for (n=1, nn, if ((n==1) || ispower(n), print1(sigma(n), ", ")););} \\ _Michel Marcus_, Oct 02 2014
%Y Cf. A000203, A001597, A076400.
%K nonn
%O 1,2
%A _Reinhard Zumkeller_, Oct 09 2002