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 A307963 Larger of coreful amicable numbers pair: numbers (m, n) such that csigma(m) = csigma(n) = m + n, where csigma(n) is the sum of the coreful divisors of n (A057723). 4

%I #10 Dec 02 2019 04:11:36

%S 2218040,4924700,6654120,15526280,14774100,28834520,37706680,42142760,

%T 34472900,46578840,51014920,64323160,68759240,64021100,82067480,

%U 86503560,90939640,95375720,104247880,83719900,113120040,117556120,93569300,126428280,103418700,130864360

%N Larger of coreful amicable numbers pair: numbers (m, n) such that csigma(m) = csigma(n) = m + n, where csigma(n) is the sum of the coreful divisors of n (A057723).

%C The terms are ordered according to the their lesser counterparts (A307962).

%H Amiram Eldar, <a href="/A307963/b307963.txt">Table of n, a(n) for n = 1..10000</a>

%t f[p_,e_] := (p^(e+1)-1)/(p-1)-1; csigma[1]=1; csigma[n_] := Times @@ (f @@@ FactorInteger[n]); s={}; Do[m = csigma[n] - n; If[m > n && csigma[m] - m == n, AppendTo[s, m]], {n, 1, 10^8}]; s

%Y Cf. A057723, A307958, A307959, A307962.

%K nonn

%O 1,1

%A _Amiram Eldar_, May 08 2019

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Last modified August 12 12:28 EDT 2024. Contains 375092 sequences. (Running on oeis4.)