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A086416
Number of divisors of 3-smooth numbers.
2
1, 2, 2, 3, 4, 4, 3, 6, 5, 6, 8, 4, 6, 9, 10, 8, 7, 12, 5, 12, 12, 8, 15, 10, 14, 16, 6, 9, 18, 15, 16, 20, 12, 10, 21, 20, 7, 18, 24, 18, 11, 24, 25, 14, 20, 28, 24, 12, 8, 27, 30, 21, 22, 32, 30, 13, 16, 30, 35, 28, 24, 9, 36, 36, 14, 24, 33, 40, 35, 26, 18, 40, 42, 15, 32
OFFSET
1,2
LINKS
FORMULA
a(n) = A000005(A003586(n)).
a(n) = if A086414(n) = A086415(n) then A086414(n)+1 else (A086414(n)+1)*(A086415(n)+1).
a(n) = (A022328(n)+1)*(A022329(n)+1).
MATHEMATICA
DivisorSigma[0, Select[Range[10000], # == 2^IntegerExponent[#, 2] * 3^IntegerExponent[#, 3] &]] (* Amiram Eldar, Apr 15 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 18 2003
STATUS
approved