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A002307 Consecutive quadratic residues mod p: a(n)=maximal number of positive reduced quadratic residues which appear consecutively for n-th prime.
(Formerly M0418 N0160)
5
1, 1, 1, 2, 3, 2, 2, 4, 4, 4, 4, 4, 3, 5, 4, 3, 5, 5, 6, 6, 4, 6, 7, 4, 4, 7, 7, 6, 5, 5, 7, 8, 6, 5, 4, 7, 6, 6, 6, 6, 6, 6, 6, 4, 7, 6, 7, 7, 7, 5, 6, 6, 6, 7, 6, 7, 8, 7, 10, 6, 9, 9, 7, 10, 5, 5, 8, 5, 8, 6, 6, 8, 9, 6, 8, 8, 8, 5, 7, 6, 8, 7, 6, 7, 10, 8, 8, 5, 8, 8, 11, 12, 8, 8, 10, 8, 9, 8, 10, 7, 9, 9, 10, 10, 7, 6, 9 (list; graph; refs; listen; history; internal format)
OFFSET

1,4

COMMENTS

When prime(n) == 3 (mod 4), then a(n)=A002308(n). - T. D. Noe, Apr 03 2007

REFERENCES

A. A. Bennett, Consecutive quadratic residues, Bull. Amer. Math. Soc., 32 (1926), 283-284.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

T. D. Noe, Table of n, a(n) for n=1..10000

MATHEMATICA

f[l_, a_] := Module[{A = Split[l], B}, B = Last[ Sort[ Cases[A, x : {a ..} :> {Length[x], Position[A, x][[1, 1]]}]]]; {First[B], Length[ Flatten[ Take[A, Last[B] - 1]]] + 1}]; g[n_] := f[ JacobiSymbol[ Range[ Prime[n] - 1], Prime[n]], 1][[1]]; Table[ g[n], {n, 2, 102}] (from Robert G. Wilson v Jul 28 2004)

CROSSREFS

Cf. A002308.

Cf. A097159

Sequence in context: A131340 A175470 A098534 * A029247 A194020 A053269

Adjacent sequences:  A002304 A002305 A002306 * A002308 A002309 A002310

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

More terms from David W. Wilson (davidwwilson(AT)comcast.net)

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Last modified February 14 11:36 EST 2012. Contains 205623 sequences.