A336355 - OEIS

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A336355

Characteristic function of A336357, numbers k for which A001221(A000203(k)) < A001221(k).

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

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OFFSET

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.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

Index entries for sequences related to sigma(n)

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

Cf. A000203, A001221, A058062, A336357, A336358.

Cf. also A336352, A336356.