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A369965

a(n) = 1 if n is of the form 4m+2 and it has an even number of prime factors with multiplicity, otherwise 0.

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

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OFFSET

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..100000

Index entries for characteristic functions

FORMULA

All these formulas should be computed with a shortcut multiplication, which ignores the right hand side expression if the left hand side yields zero:

a(n) = A121262(2+n) * A065043(n).

a(n) = A165560(n) * A065043(n).

a(n) = A059841(n) * A353558(n/2).

MATHEMATICA

A369965[n_] := Boole[Mod[n, 4] == 2 && EvenQ[PrimeOmega[n]]];