A084788 - OEIS

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A084788

Sizes of successive increasing gaps between 3-smooth numbers.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

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

Cf. A003586, A061987, A084789, A084790, A084791.

Sequence in context: A368988 A057919 A102250 * A002809 A015904 A015888

Adjacent sequences: A084785 A084786 A084787 * A084789 A084790 A084791

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jun 03 2003

STATUS

approved