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

1,2

Links

Table of n, a(n) for n=1..36.

Example

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.

Mathematica

a[n_] := Sum[k^(DivisorSigma[0, k]/2 + 1), {k, 1, n}]; Array[a, 50] (* Amiram Eldar, Aug 06 2024 *)

Crossrefs

Cf. A000027, A007955.

Sequence in context: A270208 A271463 A272425 * A270620 A270636 A077335

Adjacent sequences: A174932 A174933 A174934 * A174936 A174937 A174938

Keyword

nonn,changed

Author

Jaroslav Krizek, Apr 02 2010

Extensions

More terms from Amiram Eldar, Aug 06 2024

Status

approved