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Characteristic function of primes of form 4n+1 (1 if n is prime of form 4n+1, 0 otherwise).

+0
4

0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Let M(n) denote the n X n matrix m(i,j)=0 if n divides ij-1, m(i,j) = 1 otherwise then det(M(n))=-1 if and only if n =2 or if n is prime ==1 (mod 4).` `a(A002144(n)) = 1; a(A137409(n)) = 0. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 11 2008]`
	LINKS	`Index entries for characteristic functions`
	PROGRAM	`(PARI) { a(n)=if(n%4==1, isprime(n)) }; vector(100, n, a(n))`
	CROSSREFS	`Cf. A002144.` `Sequence in context: A011666 A011669 A023971 this_sequence A025457 A093957 A144601` `Adjacent sequences: A079257 A079258 A079259 this_sequence A079261 A079262 A079263`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 04 2003`

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Last modified December 4 15:11 EST 2009. Contains 170347 sequences.

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