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A336355
Characteristic function of A336357, numbers k for which A001221(A000203(k)) < A001221(k).
5
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, 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, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1
OFFSET
1
COMMENTS
If a(x) = a(y) = 1 and gcd(x,y) = 1, then a(x*y) = 1 also. For example, we can take x = 372 = 2^2 * 3 * 31, y = 385 = 5 * 7 * 11, and x*y = 372*385 = 143220. On all these points, a(n) = 1.
FORMULA
a(n) = 1 if A058062(n) < A001221(n), otherwise 0.
a(A336357(n)) = 1; a(A336358(n)) = 0, for all n >= 1.
PROG
(PARI) A336355(n) = (omega(sigma(n))<omega(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 20 2020
STATUS
approved