A072680 - OEIS

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A072680

Difference between (least prime >= n) and (largest prime <= n).

0, 0, 2, 0, 2, 0, 4, 4, 4, 0, 2, 0, 4, 4, 4, 0, 2, 0, 4, 4, 4, 0, 6, 6, 6, 6, 6, 0, 2, 0, 6, 6, 6, 6, 6, 0, 4, 4, 4, 0, 2, 0, 4, 4, 4, 0, 6, 6, 6, 6, 6, 0, 6, 6, 6, 6, 6, 0, 2, 0, 6, 6, 6, 6, 6, 0, 4, 4, 4, 0, 2, 0, 6, 6, 6, 6, 6, 0, 4, 4, 4, 0, 6, 6, 6, 6, 6, 0, 8, 8, 8, 8, 8, 8, 8, 0, 4, 4, 4, 0, 2, 0, 4, 4, 4 (list; graph; refs; listen; history; internal format)

	OFFSET	`2,3`
	COMMENTS	`a(n)=0 iff n is prime.`
	FORMULA	`a(n) = A057427(n - A007917(n)) * A001223(A049084(A007917(n))).`
	MATHEMATICA	`f[n_]:=If[PrimeQ[n], 0, NextPrime[n]-NextPrime[n, -1]]; Array[f, 110, 2] (* From Harvey P. Dale, Sep 22 2011 *)`
	PROG	`(Mupad) numlib::prevprime(i)(-1)-nextprime(i)(-1)$ i = 2..106 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 26 2007`
	CROSSREFS	`a(n) = A007918(n) - A007917(n).` `Cf. A072681, A013633.` `Sequence in context: A052120 A179461 A029186 * A067770 A079200 A011420` `Adjacent sequences: A072677 A072678 A072679 * A072681 A072682 A072683`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 01 2002`

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Last modified February 15 18:22 EST 2012. Contains 205835 sequences.