A369915 a(n) = Sum_{p|n, p prime} lcm(p, n/p) / p.
0, 1, 1, 1, 1, 5, 1, 2, 1, 7, 1, 7, 1, 9, 8, 4, 1, 11, 1, 9, 10, 13, 1, 14, 1, 15, 3, 11, 1, 31, 1, 8, 14, 19, 12, 13, 1, 21, 16, 18, 1, 41, 1, 15, 14, 25, 1, 28, 1, 27, 20, 17, 1, 33, 16, 22, 22, 31, 1, 47, 1, 33, 16, 16, 18, 61, 1, 21, 26, 59, 1, 26, 1, 39, 28, 23, 18
Offset: 1
Programs
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Mathematica
Table[DivisorSum[n, LCM[#, n/#]/# &, PrimeQ[#] &], {n, 100}]
Formula
a(p^k) = p^(k-2+floor(1/k)) for p prime and k>=1. - Wesley Ivan Hurt, Jul 09 2025