id:A053144 - OEIS Search Results

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Cototient of n-th primorial number.

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1, 4, 22, 162, 1830, 24270, 418350, 8040810, 186597510, 5447823150, 169904387730, 6317118448410, 260105476071210, 11228680258518030, 529602053223499410, 28154196550210460730, 1665532558389396767070 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`a(n)>A005367(n), a(n)>A002110(n)/2`
	FORMULA	`a(n)=A051593[A002110(n)]=A002110(n)-A005867(n)`
	EXAMPLE	`In the reduced residue system of q(4)=235*7-210 the number of coprimes to 210 is 48, while a(4)=210-48=162 is the number values divisible with one of the prime factors of q(4).`
	CROSSREFS	`A002110, A051593.` `Sequence in context: A122704 A087547 A000779 this_sequence A089464 A111343 A121397` `Adjacent sequences: A053141 A053142 A053143 this_sequence A053145 A053146 A053147`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), Feb 28 2000`

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

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