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A002070 Coefficient of x^p (p = n-th prime) in x * Product_{k=1..inf} (1-x^k)^2*(1-x^11k)^2.
(Formerly M0072 N0024)
3
-2, -1, 1, -2, 1, 4, -2, 0, -1, 0, 7, 3, -8, -6, 8, -6, 5, 12, -7, -3, 4, -10, -6, 15, -7, 2, -16, 18, 10, 9, 8, -18, -7, 10, -10, 2, -7, 4, -12, -6, -15, 7, 17, 4, -2, 0, 12, 19, 18, 15, 24, -30, -8, -23, -2, 14, 10, -28, -2, -18, 4, 24, 8, 12, -1, 13, 7, -22, 28, 30, -21, -20, -17, -26, -5, -1, -15, -2 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Form the infinite product x*[(1-x)*(1-x^11)*(1-x^2)*(1-x^22)*(1-x^3)*(1-x^33)*(1-x^4)*(1-x^44)*...]^2 and take the coefficients of x^2, x^3, x^5, x^7, x^11, x^13, x^17, x^19, ...

The primes p where A006571(p) == 0 (mod p) are called supersingular for the elliptic curve "11a3" and are given by sequence A006962. - Michael Somos Dec 25 2010

REFERENCES

Shimura, Goro; A reciprocity law in non-solvable extensions. J. Reine Angew. Math. 221 1966 209-220.

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

N. J. A. Sloane, Table of n, a(n) for n = 1..1229

MATHEMATICA

a[ n_] := If[ n < 1, 0, With[ {m = Prime @ n}, SeriesCoefficient[ q (Product[ (1 - q^(11 k)), {k, Ceiling[m/11]}]Product[ 1 - q^k, {k, m}])^2, {q, 0, m}]]] (* Michael Somos Jul 04 2011 *)

CROSSREFS

Cf. A006571 (all coefficients). A006962.

Sequence in context: A165585 A082506 A053000 * A106052 A050473 A057593

Adjacent sequences:  A002067 A002068 A002069 * A002071 A002072 A002073

KEYWORD

sign,easy,nice

AUTHOR

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

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Last modified February 14 18:47 EST 2012. Contains 205663 sequences.