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A295308 Characteristic function for A066694: a(n) = 1 if n < phi(sigma(n)), 0 otherwise. 2
0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 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, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 (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 if n < A062401(n), 0 otherwise.

MATHEMATICA

Array[Boole[# < EulerPhi@ DivisorSigma[1, #]] &, 120] (* Michael De Vlieger, Nov 22 2017 *)

PROG

(PARI) a(n) = n < eulerphi(sigma(n)); \\ Michel Marcus, Nov 23 2017

CROSSREFS

Cf. A000010, A000203, A062401, A066694, A295301, A295303, A295309.

Sequence in context: A285963 A024889 A101349 * A284954 A221151 A353470

Adjacent sequences:  A295305 A295306 A295307 * A295309 A295310 A295311

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 22 2017

STATUS

approved

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Last modified May 28 00:30 EDT 2022. Contains 354110 sequences. (Running on oeis4.)