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A055088 Triangle of generalized Legendre symbols L(a/b), with 1's for quadratic residues and 0's for quadratic non-residues. +0
4
1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0 (list; table; graph; listen)
OFFSET

1,1

COMMENT

For every prime of the form 4k+1 (A002144) the row is symmetric and for every prime of the form 4k+3 (A002145) the row is "complementarily symmetric".

FORMULA

[seq(quadres_0_1_array(j), j=1..)]; (See Maple code below)

EXAMPLE

Terms are L(1/2); L(1/3), L(2/3); L(1/4), L(2/4), L(3/4); L(1/5), ... where L(a/b) is 1 if an integer c exists such that c^2 is congruent to a (mod b) and 0 otherwise.

E.g. the tenth row gives the quadratic residues and non-residues of 11 (see A011582) and the twelfth row gives the same information for 13 (A011583), with -1's replaced by zeros.

MAPLE

with(numtheory, quadres); quadres_0_1_array := (n) -> one_or_zero(quadres((n-((trinv(n-1)*(trinv(n-1)-1))/2)), (trinv(n-1)+1)));

CROSSREFS

Cf. A054431 for one_or_zero and trinv. Each row interpreted as a binary number: A055094.

Sequence in context: A033788 A033782 A033778 this_sequence A068427 A164057 A140820

Adjacent sequences: A055085 A055086 A055087 this_sequence A055089 A055090 A055091

KEYWORD

nonn,tabl

AUTHOR

Antti Karttunen Apr 18 2000

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Last modified November 24 14:25 EST 2009. Contains 167438 sequences.


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