A382493 a(n) is the 2-adic valuation of the least number that has exactly n 3-smooth divisors.
0, 1, 2, 1, 4, 2, 6, 3, 2, 4, 10, 3, 12, 6, 4, 3, 16, 5, 18, 4, 6, 10, 22, 5, 4, 12, 8, 6, 28, 5, 30, 7, 10, 16, 6, 8, 36, 18, 12, 7, 40, 6, 42, 10, 8, 22, 46, 7, 6, 9, 16, 12, 52, 8, 10, 7, 18, 28, 58, 9, 60, 30, 8, 7, 12, 10, 66, 16, 22, 9, 70, 11, 72, 36, 14
Offset: 1
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
a[n_] := IntegerExponent[Min[Table[2^(d-1)*3^(n/d-1), {d, Divisors[n]}]], 2]; Array[a, 100] -
PARI
a(n) = valuation(vecmin(apply(d -> 2^(d-1)*3^(n/d-1), divisors(n))), 2);
Comments