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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.
2
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
OFFSET
1
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.
Sequence in context: A355940 A348033 A327153 * A133943 A014084 A014159
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 07 2024
STATUS
approved