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A346111
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a(n) = Sum_{primes p <=n} sigma(floor(n/p)).
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3
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0, 1, 2, 4, 5, 8, 9, 12, 13, 14, 15, 24, 25, 23, 23, 30, 31, 35, 36, 44, 41, 37, 38, 61, 60, 48, 46, 59, 60, 71, 72, 79, 74, 63, 58, 95, 96, 79, 66, 95, 96, 102, 103, 110, 108, 98, 99, 142, 138, 114, 102, 116, 117, 136, 129, 152, 134, 110, 111, 191, 192, 154, 142
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OFFSET
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1,3
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LINKS
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MATHEMATICA
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a[n_] := Plus @@ DivisorSigma[1, Floor[n/Select[Range[n], PrimeQ]]]; Array[a, 100] (* Amiram Eldar, Jul 05 2021 *)
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PROG
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(PARI) a(n) = my(s=0); forprime(p=2, n, s+=sigma(n\p)); s;
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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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