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A319710 a(n) = 1 if n is divisible by the square of its smallest prime factor, 0 otherwise. 5
0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

FORMULA

a(n) = 1 iff A067029(n) > 1.

a(n) = 1 if A020639(n)^2 divides n, otherwise 0.

a(n) = 1 iff n > 1 and A126773(n) = 1.

a(4*n) = a(18*n + 9) = 1. - David A. Corneth, Oct 04 2018

MATHEMATICA

Join[{0}, Table[If[Divisible[n, FactorInteger[n][[1, 1]]^2], 1, 0], {n, 2, 130}]] (* Harvey P. Dale, Mar 01 2019 *)

PROG

(PARI) A319710(n) = ((n>1)&&(factor(n)[1, 2]>1));

CROSSREFS

Characteristic function of A283050.

Cf. A008966, A020639, A067029, A010052, A126773, A268340, A319988.

Sequence in context: A319988 A023969 A060039 * A345951 A345952 A107078

Adjacent sequences:  A319707 A319708 A319709 * A319711 A319712 A319713

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 04 2018

STATUS

approved

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Last modified July 24 03:29 EDT 2021. Contains 346273 sequences. (Running on oeis4.)