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 A000488 Generalized tangent numbers d_(n,3). (Formerly M5024 N2167) 4
 16, 361, 3362, 16384, 55744, 152166, 355688, 739328, 1415232, 2529614, 4261454, 6885376, 10708160, 16054580, 23494584, 33554432, 46698624, 64037790, 86342918, 114163712, 149518720, 193356526, 246232840, 311635968, 390600000 (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 Lars Blomberg, Table of n, a(n) for n = 1..1000 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 MATHEMATICA amax = 25; km0 = 10; L[a_, s_, km_] := Sum[JacobiSymbol[-a, 2 k + 1]/(2 k + 1)^s, {k, 0, km}]; d[1, n_, km_] := 2 (2 n - 1)! L[-1, 2 n, km] (2/Pi)^(2 n) // Round; d[a_ /; a > 1, n_, km_] := (2 n - 1)! L[-a, 2 n, km] (2 a/Pi )^(2 n)/Sqrt[a] // Round; dd[km_] := dd[km] = Table[d[a, 3, km], {a, 1, amax}]; dd[km0]; dd[km = 2 km0]; While[dd[km] != dd[km/2, km = 2 km]]; A000488 = dd[km] (* Jean-François Alcover, Feb 08 2016 *) CROSSREFS Cf. A000061, A000176, A000518. Sequence in context: A155122 A094101 A034673 * A025759 A276257 A276097 Adjacent sequences:  A000485 A000486 A000487 * A000489 A000490 A000491 KEYWORD nonn AUTHOR EXTENSIONS More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Jun 03 2000 STATUS approved

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Last modified April 7 04:20 EDT 2020. Contains 333292 sequences. (Running on oeis4.)