A174935 a(n) = Sum_{k<=n} A007955(k) * A000027(k) = Sum_{k<=n} A007955(k) * k, where A007955(m) = product of divisors of m.
1, 5, 14, 46, 71, 287, 336, 848, 1091, 2091, 2212, 22948, 23117, 25861, 29236, 45620, 45909, 150885, 151246, 311246, 320507, 331155, 331684, 8294308, 8297433, 8315009, 8334692, 8949348, 8950189, 33250189, 33251150, 34299726, 34335663, 34374967, 34417842, 397214898
Offset: 1
Keywords
Examples
For n = 4, A007955(n) = b(n): a(4) = b(1)*1 + b(2)*2 + b(3)* 3 + b(4)*4 = 1*1 + 2*2 + 3*3 + 8*4 = 46.
Programs
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Mathematica
a[n_] := Sum[k^(DivisorSigma[0, k]/2 + 1), {k, 1, n}]; Array[a, 50] (* Amiram Eldar, Aug 06 2024 *)
Extensions
More terms from Amiram Eldar, Aug 06 2024