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A347526 Number of divisors of n that are at most n^(1/4).

%I A347526 #15 Sep 06 2021 03:03:23
%S A347526 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,
%T A347526 1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,
%U A347526 1,2,1,2,1,2,1,2,1,2,1,2,2,2,1,3,1,2,2,2,1,3,1,2,2,2,1,3,1,2,2,2,1,3,1,2,2,2,1,3
%N A347526 Number of divisors of n that are at most n^(1/4).
%H A347526 Seiichi Manyama, <a href="/A347526/b347526.txt">Table of n, a(n) for n = 1..10000</a>
%F A347526 G.f.: Sum_{k>=1} x^(k^4)/(1 - x^k).
%t A347526 a[n_] := DivisorSum[n, 1 &, # <= n^(1/4) &]; Array[a, 100] (* _Amiram Eldar_, Sep 05 2021 *)
%o A347526 (PARI) a(n) = sumdiv(n, d, d^4<=n);
%o A347526 (PARI) N=99; x='x+O('x^N); Vec(sum(k=1, N^(1/4), x^k^4/(1-x^k)))
%Y A347526 Cf. A000005, A038548, A063775, A347516, A347527.
%K A347526 nonn
%O A347526 1,16
%A A347526 _Seiichi Manyama_, Sep 05 2021