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A323152
a(n) = 1 if sigma(n) is divisible by all proper divisors of n, 0 otherwise.
2
1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1
OFFSET
1
COMMENTS
Characteristic function of A166070.
Differs from A323153 at positions n = 1, 120, 672, 30240, 32760, ...
MATHEMATICA
Table[If[AllTrue[DivisorSigma[1, n]/Most[Divisors[n]], IntegerQ], 1, 0], {n, 150}] (* Harvey P. Dale, Mar 06 2023 *)
PROG
(PARI) A323152(n) = { my(s=sigma(n)); fordiv(n, d, if((d<n)&&(s%d), return(0))); (1); };
CROSSREFS
Sequence in context: A188318 A361897 A189206 * A192280 A342005 A354355
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 09 2019
STATUS
approved