id:A074908 - OEIS Search Results

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Number of integers with an odd number of distinct primes (for which mu(n)=-1) between two consecutive primes prime(n) and prime(n+1).

+0
1

2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 3, 3, 2, 3, 2, 2, 2, 2, 3, 3, 2, 3, 3, 3, 2, 3, 2, 2, 3, 2, 3, 3, 3, 2, 5, 2, 3, 2, 2, 3, 2, 2, 4, 3, 2, 3, 3, 3, 3, 2, 3, 2, 3, 5, 2, 3, 2, 2, 4, 2, 3, 2, 2, 4, 3, 3, 3, 2, 3, 2, 3, 4, 4, 2, 5, 2, 5, 3, 2, 3, 2, 2, 3, 4, 3, 2, 4, 2, 3, 3, 2, 4, 2, 3, 3, 2, 2, 3 (list; graph; listen)

	OFFSET	`0,1`
	EXAMPLE	`Between 7919 and 7927 the 5 numbers which have an odd number of distinct primes are as follows: {7919,7922,7923,7926,7927}, so a(1000)=5.`
	MAPLE	`readlib(issqr): lstmp := proc(n) local t1, i; t1 := 0; for i from ithprime(n) to ithprime(n+1) do if (issqrfree(i) = 'true' and mobius(i)=-1) then t1 := t1+1; fi; od; t1; end: lstmp(200);`
	CROSSREFS	`Cf. A061265, A061399.` `Sequence in context: A103663 A083311 A037968 this_sequence A151963 A111858 A111856` `Adjacent sequences: A074905 A074906 A074907 this_sequence A074909 A074910 A074911`
	KEYWORD	`nonn`
	AUTHOR	`Jani Melik (jani_melik(AT)hotmail.com), Sep 30 2002`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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