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A064073 Generalized tangent number d(8,n). 2
8, 1408, 739328, 806453248, 1506300919808, 4297849713983488, 17390688314209599488, 94727563504456856240128, 668321603392783694711226368, 5928595592752632717848942215168 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Lars Blomberg, Table of n, a(n) for n = 1..177

D. Shanks, Generalized Euler and class numbers. Math. Comp. 21 (1967) 689-694.

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

Eric Weisstein's World of Mathematics, Tangent Number.

FORMULA

E.g.f.: Sum_{k>0} a(k)x^(2k-1)/(2k-1)! = 2*sin(4x)/cos(8x).

Equals 2^(4n-1) * A000464(n-1).

CROSSREFS

Cf. A064072.

Sequence in context: A230472 A160103 A283902 * A282889 A225068 A270145

Adjacent sequences:  A064070 A064071 A064072 * A064074 A064075 A064076

KEYWORD

nonn,easy

AUTHOR

Eric W. Weisstein, Aug 31 2001

STATUS

approved

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Last modified October 23 23:51 EDT 2019. Contains 328379 sequences. (Running on oeis4.)