A078442 - OEIS

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A078442

a(p(n))=a(n)+1 for n-th prime p(n); a(n)=0 if n is not prime.

0, 1, 2, 0, 3, 0, 1, 0, 0, 0, 4, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 5, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 3, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	COMMENTS	`Fernandez calls this the order of primeness of n.`
	LINKS	`N. Fernandez, An order of primeness, F(p)`
	EXAMPLE	`a(1)=0 since 1 is not prime; a(2)=a(p(1))=a(1)+1=1+0=1; a(3)=a(p(2))=a(2)+1=1+1=2; a(4)=0 since 4 is not prime; a(5)=a(p(3))=a(3)+1=2+1=3; a(6)=0 since 6 is not prime; a(7)=a(p(4))=a(4)+1=0+1=1.`
	PROG	`(PARI) A078442(n)=for(i=0, n, isprime(n) \| return(i); n=primepi(n)) [From M. F. Hasler (www.univ-ag.fr/~mhasler), Mar 09 2010]`
	CROSSREFS	`a(A000040(n)) = A049076(n).` `Sequence in context: A113303 A080089 A113290 * A175663 A135523 A194663` `Adjacent sequences: A078439 A078440 A078441 * A078443 A078444 A078445`
	KEYWORD	`nonn`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Dec 31 2002`

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Last modified February 17 11:46 EST 2012. Contains 206011 sequences.