A174933 a(n) = Sum_{d|n} A007955(d) * A000027(d) = Sum_{d|n} A007955(d) * (d), where A007955(m) = product of divisors of m.
1, 5, 10, 37, 26, 230, 50, 549, 253, 1030, 122, 20998, 170, 2798, 3410, 16933, 290, 105449, 362, 161062, 9320, 10774, 530, 7984134, 3151, 17750, 19936, 617486, 842, 24304630, 962, 1065509, 36068, 39598, 42950, 362923273, 1370, 55238, 59498, 102561574
Offset: 1
Keywords
Examples
For n = 4, A007955(n) = b(n): a(4) = b(1)*1 + b(2)*2 + b(4)*4 = 1*1 + 2*2 + 8*4 = 37.
Links
- Andrew Howroyd, Table of n, a(n) for n = 1..1000
Crossrefs
Cf. A007955.
Programs
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Magma
[&+[&*Divisors(d)*d:d in Divisors(n)]:n in [1..40]]; // Marius A. Burtea, Jan 05 2020
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PARI
a(n)={sumdiv(n, d, vecprod(divisors(d))*d)} \\ Andrew Howroyd, Jan 05 2020
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Python
from math import isqrt from sympy import divisor_count, divisors def A174933(n): return sum(isqrt(d)**(c+2) if (c:=divisor_count(d)) & 1 else d**(c//2+1) for d in divisors(n,generator=True)) # Chai Wah Wu, Jun 25 2022
Extensions
Terms a(31) and beyond from Andrew Howroyd, Jan 05 2020