A353483 - OEIS

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A353483

a(n) = 1 if n is a squarefree semiprime of the form (4t+3)*(4u+3), otherwise 0.

6

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

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OFFSET

1

LINKS

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

Index entries for characteristic functions

FORMULA

a(n) = A353482(n) * A353492(n).

a(n) = A064911(n) * A353809(n), a(n) <= A353808(n). - Antti Karttunen, May 13 2022

PROG

(PARI)

A032742(n) = if(1==n, n, n/vecmin(factor(n)[, 1]));

A353492(n) = (3==(A032742(n)%4));

A353482(n) = ((2==bigomega(n)) && (2==omega(n)) && (1==(n%4)));

A353483(n) = (A353492(n)*A353482(n));

CROSSREFS

Characteristic function of A016105, Blum integers.

Cf. A064911, A353481, A353482, A353492, A353808, A353809.

Sequence in context: A085982 A011735 A355816 * A353809 A353808 A353482

Adjacent sequences: A353480 A353481 A353482 * A353484 A353485 A353486

KEYWORD

nonn

AUTHOR

Antti Karttunen, Apr 22 2022

STATUS

approved