The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A186928 Greater of two consecutive 3-smooth numbers having no common divisors. 4
 2, 3, 4, 9, 32, 256, 2187, 531441, 134217728, 70368744177664, 36893488147419103232, 19383245667680019896796723, 713623846352979940529142984724747568191373312, 13803492693581127574869511724554050904902217944340773110325048447598592 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = A003586(A186771(n) + 1); A186927(n) = A003586(A186771(n)); also a subsequence of A006899: all terms are either powers of 2 or of 3. LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..20 MATHEMATICA smoothNumbers[p_, max_] := Module[{a, aa, k, pp, iter}, k = PrimePi[p]; aa = Array[a, k]; pp = Prime[Range[k]]; iter = Table[{a[j], 0, PowerExpand @ Log[pp[[j]], max/Times @@ (Take[pp, j - 1]^Take[aa, j - 1])]}, {j, 1, k}]; Table[Times @@ (pp^aa), Sequence @@ iter // Evaluate] // Flatten // Sort]; sn = smoothNumbers[3, 10^100]; Reap[For[i = 1, i <= Length[sn] - 1, i++, If[CoprimeQ[sn[[i]], sn[[i + 1]]], Sow[sn[[i + 1]]]]]][[2, 1]] (* Jean-François Alcover, Nov 11 2016 *) CROSSREFS Subsequence of A006899. Cf. A186711. Sequence in context: A059972 A245930 A086432 * A076018 A076017 A245366 Adjacent sequences:  A186925 A186926 A186927 * A186929 A186930 A186931 KEYWORD nonn AUTHOR Charles R Greathouse IV and Reinhard Zumkeller, Mar 01 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 26 11:11 EDT 2022. Contains 354881 sequences. (Running on oeis4.)