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A085129
Multiples of 6 which are 7-smooth.
7
6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 72, 84, 90, 96, 108, 120, 126, 144, 150, 162, 168, 180, 192, 210, 216, 240, 252, 270, 288, 294, 300, 324, 336, 360, 378, 384, 420, 432, 450, 480, 486, 504, 540, 576, 588, 600, 630, 648, 672, 720, 750, 756, 768, 810, 840
OFFSET
1,1
COMMENTS
Equivalently, multiples of 6 with the largest prime divisor < 10.
FORMULA
From Amiram Eldar, Sep 22 2024: (Start)
a(n) = 6*A002473(n).
Sum_{n>=1} 1/a(n) = 35/48. (End)
MATHEMATICA
With[{p = Prime[Range[4]]}, 6 * Select[Range[140], Times @@ (p^IntegerExponent[#, p]) == # &]] (* Amiram Eldar, Sep 23 2024 *)
CROSSREFS
Intersection of A008588 and A002473.
Sequence in context: A008588 A078596 A187389 * A236240 A242650 A083263
KEYWORD
nonn,easy
AUTHOR
Amarnath Murthy, Jul 06 2003
EXTENSIONS
More terms from David Wasserman, Jan 28 2005
Offset changed by Andrew Howroyd, Sep 19 2024
STATUS
approved