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A350961
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a(n) = Sum_{k=1..n} 3^Omega(k).
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4
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1, 4, 7, 16, 19, 28, 31, 58, 67, 76, 79, 106, 109, 118, 127, 208, 211, 238, 241, 268, 277, 286, 289, 370, 379, 388, 415, 442, 445, 472, 475, 718, 727, 736, 745, 826, 829, 838, 847, 928, 931, 958, 961, 988, 1015, 1024, 1027, 1270, 1279, 1306, 1315, 1342, 1345, 1426, 1435, 1516, 1525, 1534, 1537, 1618
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OFFSET
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1,2
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REFERENCES
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Tenenbaum, G. (2015). Introduction to analytic and probabilistic number theory, 3rd ed., American Mathematical Soc. See page 59.
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LINKS
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MATHEMATICA
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PROG
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(Python)
from sympy.ntheory.factor_ import primeomega
def A350961(n): return sum(3**primeomega(m) for m in range(1, n+1)) # Chai Wah Wu, Sep 07 2023
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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