id:A106571 - OEIS Search Results

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Indices n of perfect squares n^2 which are not the difference of two primes.

+0
16

5, 7, 11, 13, 17, 19, 23, 25, 27, 29, 31, 35, 37, 41, 43, 47, 49, 51, 53, 55, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 83, 85, 87, 89, 91, 93, 95, 97, 101, 103, 107, 109, 113, 115, 119, 121, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 149, 151, 153, 155 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Also, n such that 1+n^2 is a nontotient (A005277). - T. D. Noe, Sep 13 2007`
	LINKS	`T. D. Noe, Table of n, a(n) for n=1..1000`
	FORMULA	`a(n) = SQRT(A106564(n)).`
	EXAMPLE	`a(3)=11 because the third square which is not the difference of two primes (121=11^2) is the 11-th one in the succession of the perfect squares (thus index 11).`
	CROSSREFS	`Cf. A106544-A106548, A106562-A106564, A106573-A106575, A106577.` `Cf. A067201 (n such that n^2+2 is prime)` `Sequence in context: A111906 A101550 A136801 this_sequence A067291 A007310 A069040` `Adjacent sequences: A106568 A106569 A106570 this_sequence A106572 A106573 A106574`
	KEYWORD	`easy,nonn`
	AUTHOR	`Alexandre Wajnberg (alexandre.wajnberg(AT)ulb.ac.be), May 09 2005`
	EXTENSIONS	`Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), May 12 2005`

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.

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