A374197 - OEIS

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A374197

a(n) is 1 if the minimum value of A017666 that it obtains among divisors of n larger than 1 is 1, otherwise 0. By convention a(1) = 1.

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

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OFFSET

LINKS

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

Index entries for characteristic functions

FORMULA

a(n) = [A374196(n) == 1], where [ ] is the Iverson bracket.

PROG

(PARI) A374197(n) = { my(m=0, x); fordiv(n, d, if(d>1, x = denominator(sigma(d)/d); if(!m || x<m, m=x))); (!m || (1==m)); };

CROSSREFS

Characteristic function of A374198.

Cf. A007691, A017666, A374196.