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A086299 a(n) = if n is 7-smooth then 1 else 0: characteristic function of 7-smooth numbers. 3
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(A002473(n)) = 1; a(A068191(n)) = 0. [Reinhard Zumkeller, Apr 01 2012]

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Smooth Number

Index entries for characteristic functions

FORMULA

Multiplicative with: a(p) = if p<=7 then 1 else 0, p prime.

MATHEMATICA

Table[If[Max[Transpose[FactorInteger[n]][[1]]]<11, 1, 0], {n, 110}] (* Harvey P. Dale, Oct 08 2013 *)

PROG

(Haskell)

a086299 = fromEnum . (<= 7) . a006530  -- Reinhard Zumkeller, Apr 01 2012

CROSSREFS

Cf. A002473, A006530.

Sequence in context: A137794 A105586 A136522 * A152066 A122255 A122261

Adjacent sequences:  A086296 A086297 A086298 * A086300 A086301 A086302

KEYWORD

nonn,mult

AUTHOR

Reinhard Zumkeller, Jul 15 2003

STATUS

approved

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Last modified November 21 05:01 EST 2017. Contains 294988 sequences.