A355454 - OEIS

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A355454

a(n) = 1 if the fourth smallest divisor of n is a square, otherwise 0.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0

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OFFSET

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..100000

Index entries for characteristic functions

PROG

(PARI) A355454(n) = ((numdiv(n)>3) && issquare(divisors(n)[4]));

CROSSREFS

Characteristic function of A355455.

Cf. also A355453.

Sequence in context: A297041 A355444 A070109 * A107846 A354983 A179801

Adjacent sequences: A355451 A355452 A355453 * A355455 A355456 A355457

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jul 02 2022

STATUS

approved