A344133 a(n) = Sum_{i|n, j|n, k|n} i*j*k/gcd(i,j,k).

1, 23, 46, 219, 116, 1058, 218, 1507, 883, 2668, 518, 10074, 716, 5014, 5336, 8819, 1208, 20309, 1502, 25404, 10028, 11914, 2186, 69322, 5691, 16468, 12628, 47742, 3452, 122728, 3938, 46995, 23828, 27784, 25288, 193377, 5588, 34546, 32936, 174812, 6848, 230644, 7526, 113442, 102428, 50278, 8978

Offset

1,2

Links

Table of n, a(n) for n=1..47.

Formula

If p is prime, a(p) = 1 + 3*p + 4*p^2.

Mathematica

a[n_]:= Sum[i*j*k/GCD[i, j, k], {i, (d = Divisors[n])}, {j, d}, {k, d}]; Array[a, 50] (* Amiram Eldar, May 10 2021 *)

Prog

(PARI) a(n) = sumdiv(n, i, sumdiv(n, j, sumdiv(n, k, i*j*k/gcd([i, j, k]))));

Crossrefs

Cf. A064950, A344132, A344134, A344135.

Sequence in context: A008605 A038152 A358684 * A103629 A253177 A109996

Adjacent sequences: A344130 A344131 A344132 * A344134 A344135 A344136

Keyword

nonn,mult

Author

Seiichi Manyama, May 10 2021

Status

approved