A344573 a(n) = Sum_{d|n} phi(d!).
1, 2, 3, 10, 33, 196, 1153, 9226, 82947, 829474, 8294401, 99533004, 1194393601, 16721511554, 250822656035, 4013162505226, 64210599936001, 1155790798931140, 20804234379264001, 416084687586109482, 8737778439290881155, 192231125664407654402, 4229084764616785920001
Offset: 1
Keywords
Examples
a(6) = Sum_{d|6} phi(d!) = phi(1!) + phi(2!) + phi(3!) + phi(6!) = 1 + 1 + 2 + 192 = 196.
Programs
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Mathematica
Table[Sum[EulerPhi[k!] (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 30}]
Comments