A353478 - OEIS

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A353478

a(n) = 1 if n is an even semiprime (2*prime), otherwise 0.

0, 0, 0, 1, 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, 0, 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, 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, 1, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1`
	LINKS	`Antti Karttunen, Table of n, a(n) for n = 1..65537` `Index entries for characteristic functions`
	FORMULA	`If A000035(n) = 0, then a(n) = A010051(n/2), otherwise 0.` `a(n) = A059841(n) * A064911(n).` `a(n) = A064911(n) - A353480(n).`
	PROG	`(PARI) A353478(n) = ((0==(n%2)) && isprime(n/2));`
	CROSSREFS	`Characteristic function of A100484, the primes doubled.` `Cf. A000035, A010051, A059841, A064911, A353477, A353479, A353480.` `Sequence in context: A234577 A038189 A072783 * A353555 A353476 A288377` `Adjacent sequences: A353475 A353476 A353477 * A353479 A353480 A353481`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen, Apr 22 2022`
	STATUS	`approved`

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Last modified February 27 16:39 EST 2023. Contains 360706 sequences. (Running on oeis4.)