A084790 Increasing gaps between 3-smooth numbers (upper end).

2, 6, 12, 16, 24, 48, 96, 128, 192, 288, 324, 384, 576, 648, 729, 864, 972, 1152, 1296, 1458, 1728, 1944, 2592, 2916, 3456, 3888, 5184, 5832, 7776, 10368, 11664, 15552, 23328, 31104, 46656, 93312, 177147, 209952, 236196, 279936, 314928

Offset: 1

Author

Reinhard Zumkeller, Jun 03 2003

Keywords

• nonn

Links

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

Crossrefs

Cf. A003586, A061987, A084788, A084789, A084791.

Programs

Mathematica

s = {}; m = 13; Do[n = 3^k; While[n <= 3^m, AppendTo[s, n]; n*=2], {k, 0, m}]; s = Union[s]; d = Differences @ s; v = DeleteDuplicates @ FoldList[Max, d]; Map[s[[1 + First@ Position[d, #]]] &, v] //Flatten (* Amiram Eldar, Jan 30 2020 *)

Formula

a(n) = A084788(n) + A084789(n).

a(n) = A003586(A084791(n) + 1).