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A000191 Generalized tangent numbers d(3,n).
(Formerly M2166 N0864)
9
2, 46, 3362, 515086, 135274562, 54276473326, 30884386347362, 23657073914466766, 23471059057478981762, 29279357851856595135406, 44855282210826271011257762, 82787899853638102222862479246 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

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

Sean A. Irvine, Table of n, a(n) for n = 1..250

D. Shanks, Generalized Euler and class numbers. Math. Comp. 21 1967 663-688.

D. Shanks, Corrigenda to: "Generalized Euler and class numbers", Math. Comp. 22 (1968), 699

D. Shanks, Generalized Euler and class numbers, Math. Comp. 21 (1967), 689-694; 22 (1968), 699. [Annotated scanned copy]

Eric Weisstein's World of Mathematics, Tangent Number

FORMULA

a(n) = 2*A002439(n). - N. J. A. Sloane, Nov 06 2009

MATHEMATICA

L[ a_, s_, t_:10000 ] := Plus@@Table[ N[ JacobiSymbol[ -a, 2k+1 ](2k+1)^(-s), 30 ], {k, 0, t} ]; d[ a_, n_, t_:10000 ] := (2n-1)!/Sqrt[ a ](2a/Pi)^(2n)L[ -a, 2n, t ] (* Eric W. Weisstein, Aug 30 2001 *)

CROSSREFS

Cf. A000192, A002439, A002437, A156172.

Sequence in context: A173586 A074041 A277554 * A000192 A196197 A273380

Adjacent sequences:  A000188 A000189 A000190 * A000192 A000193 A000194

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Eric W. Weisstein, Aug 30 2001

STATUS

approved

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Last modified November 19 04:01 EST 2017. Contains 294912 sequences.