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Revision History for A086247

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A086247

Differences of successive 7-smooth numbers.
(history; published version)

#13 by Wesley Ivan Hurt at Sun Oct 17 04:18:44 EDT 2021

STATUS

proposed

approved

#12 by Michel Marcus at Sun Oct 17 02:40:11 EDT 2021

STATUS

editing

proposed

#11 by Michel Marcus at Sun Oct 17 02:40:07 EDT 2021

COMMENTS

a(n) = A002473(n+1) - A002473(n);

FORMULA

a(n) = A002473(n+1) - A002473(n).

CROSSREFS

Cf. A002473, A061987, A085153.

STATUS

proposed

editing

#10 by Jean-François Alcover at Sun Oct 17 02:38:14 EDT 2021

STATUS

editing

proposed

#9 by Jean-François Alcover at Sun Oct 17 02:38:07 EDT 2021

MATHEMATICA

smooth7Q[n_] := n == Times@@({2, 3, 5, 7}^IntegerExponent[n, {2, 3, 5, 7}]);

Select[Range[1000], smooth7Q] // Differences (* Jean-François Alcover, Oct 17 2021 *)

STATUS

approved

editing

#8 by Alois P. Heinz at Wed Mar 31 09:40:15 EDT 2021

STATUS

editing

approved

#7 by Alois P. Heinz at Wed Mar 31 09:40:06 EDT 2021

KEYWORD

nonn,look,changed

STATUS

proposed

editing

#6 by David A. Corneth at Wed Mar 31 07:29:45 EDT 2021

STATUS

editing

proposed

Discussion

Wed Mar 31

07:30

David A. Corneth: keyword look?

#5 by David A. Corneth at Wed Mar 31 07:29:41 EDT 2021

EXAMPLE

a(23) = 3 as A002473(23 + 1) - A002473(23) = 35 - 32 = 3. - David A. Corneth, Mar 31 2021

#4 by David A. Corneth at Wed Mar 31 07:28:46 EDT 2021

LINKS

David A. Corneth, <a href="/A086247/b086247.txt">Table of n, a(n) for n = 1..10000</a>

STATUS

approved

editing