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A088244
Number of 3-smooth divisors of n!.
1
1, 1, 2, 4, 8, 8, 15, 15, 24, 40, 45, 45, 66, 66, 72, 84, 112, 112, 153, 153, 171, 190, 200, 200, 253, 253, 264, 336, 364, 364, 405, 405, 480, 512, 528, 528, 630, 630, 648, 684, 741, 741, 800, 800, 840, 924, 946, 946, 1081, 1081, 1104, 1152, 1200, 1200
OFFSET
0,3
LINKS
FORMULA
a(n) = A072078(A000142(n)).
a(n) = a(n-1) iff gcd(n,6) = 1.
a(n) = (A011371(n)+1)*(A054861(n)+1).
MATHEMATICA
a[n_] := ((1 + IntegerExponent[n!, 2])*(1 + IntegerExponent[n!, 3])); Array[a, 100, 0] (* Amiram Eldar, Aug 30 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jan 23 2004
STATUS
approved