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A347718
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a(n) = Sum of the divisors of sigma_n(n).
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2
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1, 6, 56, 448, 6264, 96348, 1559520, 16908804, 391945400, 20553536052, 706019328000, 20210523379200, 519285252355776, 21710734431216480, 1456143373228677120, 25536237889612326912, 1792353900753729655758, 52839150354952425838080, 4154723599066412190910560
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = sigma(sigma_n(n)).
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EXAMPLE
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a(3) = sigma(sigma_3(3)) = sigma(1^3+3^3) = sigma(28) = 1+2+4+7+14+28 = 56.
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MAPLE
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a:= n-> (s-> s(s[n](n)))(numtheory[sigma]):
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MATHEMATICA
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Table[DivisorSigma[1, DivisorSigma[n, n]], {n, 20}]
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PROG
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(Python)
from math import prod
from collections import Counter
from sympy import factorint
def A347718(n): return prod((q**(r+1)-1)//(q-1) for q, r in sum((Counter(factorint((p**(n*(e+1))-1)//(p**n-1))) for p, e in factorint(n).items()), Counter()).items()) # Chai Wah Wu, Jan 28 2022
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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