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A226520 Irregular triangle read by rows: T(n,k) = Legendre(k,prime(n)), for 0 <= k < prime(n). 7
0, 1, 0, 1, -1, 0, 1, -1, -1, 1, 0, 1, 1, -1, 1, -1, -1, 0, 1, -1, 1, 1, 1, -1, -1, -1, 1, -1, 0, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 0, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, -1, -1, 1, -1, 1, 1, 0, 1, -1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1

COMMENTS

Strictly speaking, the symbol in the definition is the Legendre-Jacobi-Kronecker symbol, since the Legendre symbol is defined only for odd primes.

REFERENCES

R. Ayoub, An Introduction to the Analytic Theory of Numbers, Amer. Math. Soc., 1963; p. 289.

Beck, József. Inevitable randomness in discrete mathematics. University Lecture Series, 49. American Mathematical Society, Providence, RI, 2009. xii+250 pp. ISBN: 978-0-8218-4756-5; MR2543141 (2010m:60026). See page 23.

H. Cohen, A Course in Computational Alg. No. Theory, Springer, 1993, p. 28.

LINKS

Reinhard Zumkeller, Rows n = 1..75 of triangle, flattened

D. A. Burgess, The distribution of quadratic residues and non-residues, Mathematika 4, 1957, 106--112. MR0093504 (20 #28)

Wikipedia, Legendre symbol.

FORMULA

See A226518 for bounds.

EXAMPLE

Triangle begins

[0, 1],

[0, 1, -1],

[0, 1, -1, -1, 1],

[0, 1, 1, -1, 1, -1, -1],

[0, 1, -1, 1, 1, 1, -1, -1, -1, 1, -1],

[0, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1],

[0, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, -1, -1, 1, -1, 1, 1],

...

MAPLE

with(numtheory);

T:=(n, k)->legendre(k, ithprime(n));

f:=n->[seq(T(n, k), k=0..ithprime(n)-1)];

[seq(f(n), n=1..15)];

MATHEMATICA

Table[p = Prime[n]; Table[JacobiSymbol[k, p], {k, 0, p-1}], {n, 1, 15}] // Flatten (* Jean-François Alcover, Mar 07 2014 *)

PROG

(Haskell)

a226520 n k = a226520_tabf !! (n-1) !! k

a226520_row n = a226520_tabf !! (n-1)

a226520_tabf =

   map (\p -> map (flip legendreSymbol p) [0..p-1]) a000040_list

-- where the function legendreSymbol is defined in A097343.

-- Reinhard Zumkeller, Feb 02 2014

CROSSREFS

Row sums give A226518.

See A097343 for another version.

Sequence in context: A295893 A157412 A023532 * A268921 A327180 A030308

Adjacent sequences:  A226517 A226518 A226519 * A226521 A226522 A226523

KEYWORD

sign,tabf

AUTHOR

N. J. A. Sloane, Jun 19 2013

STATUS

approved

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Last modified October 18 06:50 EDT 2021. Contains 348066 sequences. (Running on oeis4.)