A140482 a(n) = 2*n + tau(n).
3, 6, 8, 11, 12, 16, 16, 20, 21, 24, 24, 30, 28, 32, 34, 37, 36, 42, 40, 46, 46, 48, 48, 56, 53, 56, 58, 62, 60, 68, 64, 70, 70, 72, 74, 81, 76, 80, 82, 88, 84, 92, 88, 94, 96, 96, 96, 106, 101, 106, 106, 110, 108, 116, 114, 120, 118, 120, 120, 132, 124, 128, 132, 135, 134, 140
Offset: 1
Programs
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Mathematica
a[n_] := 2*n + DivisorSigma[0, n]; Array[a, 100] (* Amiram Eldar, Apr 07 2024 *)
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PARI
a(n) = 2*n + numdiv(n); \\ Amiram Eldar, Apr 07 2024