A161911 - OEIS

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A161911

N-th difference between consecutive primes minus the number of divisors of n.

0, 0, 0, 1, 0, 0, 0, 0, 3, -2, 4, -2, 0, 0, 2, 1, 0, 0, 2, -4, 2, 0, 4, 0, 1, -2, 0, -4, 2, 6, 2, 0, -2, 6, -2, -3, 4, 0, 2, -2, 0, 2, 0, -2, -4, 8, 10, -6, -1, -2, 2, -4, 8, -2, 2, -2, -2, 2, 2, -10, 8, 10, -2, -5, 0, 6, 4, 4, -2, -4, 4, -4, 4, 2, -2, 0, 4, -4, 6, 0, -3, 6, 0, -6, 0, 2, 4, -4 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,9`
	LINKS	`O. E. Pol, Illustration: Divisors and pi(x)`
	FORMULA	`a(n) = A001223(n) - A000005(n).`
	MAPLE	`A001223 := proc(n) ithprime(n+1)-ithprime(n) ; end: A000005 := proc(n) numtheory[tau](n) ; end: A161911 := proc(n) A001223(n)-A000005(n) ; end: seq(A161911(n), n=1..120) ; [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 01 2009]`
	CROSSREFS	`Cf. A000005, A001223, A161912.` `Sequence in context: A134029 A117623 A145690 * A139583 A073314 A144808` `Adjacent sequences: A161908 A161909 A161910 * A161912 A161913 A161914`
	KEYWORD	`easy,sign`
	AUTHOR	`Omar E. Pol (info(AT)polprimos), Jun 28 2009`
	EXTENSIONS	`More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 01 2009`

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.