id:A071854 - OEIS Search Results

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a(n) = (number of distinct prime factors in C(2n,n)) - pi(n).

+0
1

1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 2, 1, 2, 1, 2, 2, 2, 0, 1, 1, 1, 1, 3, 3, 2, 1, 2, 3, 3, 3, 3, 2, 3, 2, 3, 2, 3, 2, 2, 3, 3, 2, 3, 3, 3, 3, 3, 3, 4, 3, 3, 3, 4, 3, 4, 3, 3, 3, 4, 4, 5, 5, 4, 4, 4, 3, 4, 3, 3, 4, 4, 5, 5, 4, 5, 5, 5, 4, 4, 4, 5, 5, 5, 4, 4, 5, 6, 5, 5, 5, 6, 5, 4, 5, 6, 5, 6, 5, 6, 6 (list; graph; listen)

	OFFSET	`1,16`
	LINKS	`T. D. Noe, Table of n, a(n) for n=1..1000`
	FORMULA	`a(n) = A067434(n) - A000720(n)`
	PROGRAM	`(PARI) for(n=1, 200, print1(omega(binomial(2*n, n))-sum(i=1, n, isprime(i)), ", "))`
	CROSSREFS	`Sequence in context: A118459 A083870 A052299 this_sequence A072410 A072491 A051034` `Adjacent sequences: A071851 A071852 A071853 this_sequence A071855 A071856 A071857`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 09 2002`

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Last modified December 9 14:43 EST 2009. Contains 170430 sequences.

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