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A121743 Values of the Ramanujan tau triples mod 691 such that three consecutive Ramanujan tau numbers are congruent mod 691. 4
0, 276, 91, 79, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Corresponding indices of the Ramanujan tau triples mod 691 are listed in A121742[n] = {290217,477155,1051085,1153412,1409635,1409636,...}. All a(n) belong to the Ramanujan tau twins mod 691 A121734[n]. There are also quadruplets in the Ramanujan tau mod 691 such that A046694[n] = A046694[n+1] = A046694[n+2] = A046694[n+3]. The first such Ramanujan tau Quadruplet mod 691 starts with A046694[1409635] = 0.

LINKS

Table of n, a(n) for n=1..6.

Eric Weisstein Ramanujan's Tau Function.

FORMULA

a(n) = A000594[A121742[n]] mod 691. a(n) = A046694[A121742[n]].

MATHEMATICA

Do[f=Mod[DivisorSigma[11, n], 691]; g=Mod[DivisorSigma[11, n+1], 691]; h=Mod[DivisorSigma[11, n+2], 691]; If[f==g&&g==h, Print[{n, f}]], {n, 1, 1500000}]

CROSSREFS

Cf. A121742, A121733, A121734, A046694, A000594.

Sequence in context: A133536 A224109 A075666 * A084802 A309998 A003903

Adjacent sequences:  A121740 A121741 A121742 * A121744 A121745 A121746

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Aug 19 2006

STATUS

approved

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Last modified November 20 05:07 EST 2019. Contains 329323 sequences. (Running on oeis4.)