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A337345 Number of divisors d of n for which A003961(d) > 2*d. 10

%I #10 Aug 27 2020 08:57:35

%S 0,0,0,1,0,1,0,2,1,1,0,3,0,1,1,3,0,3,0,3,1,0,0,5,0,0,2,3,0,4,0,4,0,0,

%T 1,6,0,0,1,5,0,4,0,2,3,0,0,7,1,2,0,2,0,5,0,5,1,0,0,8,0,0,3,5,0,2,0,2,

%U 1,4,0,9,0,0,2,2,0,3,0,7,3,0,0,8,0,0,0,4,0,8,1,2,0,0,0,9,0,3,2,5,0,2,0,4,4

%N Number of divisors d of n for which A003961(d) > 2*d.

%C Number of terms of A246282 that divide n.

%C Number of divisors d of n for which A048673(d) > d.

%H Antti Karttunen, <a href="/A337345/b337345.txt">Table of n, a(n) for n = 1..65537</a>

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%F a(n) = Sum_{d|n} A252742(d).

%F a(n) = A337346(n) + A252742(n).

%o (PARI)

%o A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };

%o A337345(n) = sumdiv(n,d,A003961(d)>(d+d));

%Y Inverse Möbius transform of A252742.

%Y Cf. A003961, A048673, A246282, A337346, A337372 (positions of ones).

%Y Cf. also A080224.

%K nonn

%O 1,8

%A _Antti Karttunen_, Aug 27 2020

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Last modified April 20 00:03 EDT 2024. Contains 371798 sequences. (Running on oeis4.)