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A084788
Sizes of successive increasing gaps between 3-smooth numbers.
6
1, 2, 3, 4, 6, 12, 15, 20, 30, 32, 36, 60, 64, 72, 81, 96, 108, 128, 144, 162, 192, 216, 288, 324, 384, 432, 576, 648, 864, 1152, 1296, 1728, 2592, 3456, 5184, 10368, 11259, 13344, 15012, 17792, 20016, 22518, 26688, 30024, 40032, 45036, 53376
OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Smooth Number
FORMULA
a(n) = A084790(n) - A084789(n).
a(n) = A061987(A084791(n)).
MATHEMATICA
s = {}; m = 13; Do[n = 3^k; While[n <= 3^m, AppendTo[s, n]; n*=2], {k, 0, m}]; DeleteDuplicates @ FoldList[Max, Differences @ Union[s]] (* Amiram Eldar, Jan 30 2020 *)
DeleteDuplicates[Differences[Select[Range[10^6], Max[FactorInteger[#][[All, 1]]]<5&]], GreaterEqual] (* Harvey P. Dale, Nov 22 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jun 03 2003
STATUS
approved