A163975 - OEIS

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A163975

n-th nonprime-(-1)^(n-th nonprime).

-1, 2, 3, 5, 7, 10, 9, 11, 13, 16, 15, 17, 19, 22, 21, 23, 26, 25, 28, 27, 29, 31, 34, 33, 36, 35, 37, 40, 39, 41, 43, 46, 45, 47, 50, 49, 52, 51, 53, 56, 55, 58, 57, 59, 61, 64, 63, 66, 65, 67, 70, 69, 71, 73, 76, 75, 78, 77, 79, 82, 81, 83, 86, 85, 88, 87, 89, 92, 91, 94, 93 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	FORMULA	`a(n)=A141468(n)-(-1)^A141468(n).` `a(n)= A103889(A141468(n)), n>0.`
	EXAMPLE	`a(1)=0-(-1)^0=-1. a(2)=1-(-1)^1=2.`
	MAPLE	`A103889 := proc(n) n-(-1)^n ; end:` `A141468 := proc(n) option remember ; if n <= 2 then n-1 ; else for a from procname(n-1)+1 do if not isprime(a) then RETURN(a); fi; od: fi; end:` `A163975 := proc(n) A103889(A141468(n)) ; end: seq( A163975(n), n=1..120) ;`
	CROSSREFS	`Cf. A141468.` `Sequence in context: A108031 A076387 A193622 * A202267 A125975 A046758` `Adjacent sequences: A163972 A163973 A163974 * A163976 A163977 A163978`
	KEYWORD	`sign,easy`
	AUTHOR	`Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Aug 07 2009`
	EXTENSIONS	`Entries checked by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 29 2009`

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Last modified February 17 06:27 EST 2012. Contains 205998 sequences.