A064072 - OEIS

%I #23 Nov 22 2021 02:35:54

%S 8,904,355688,296327464,423645846728,925434038426824,

%T 2866986638191472168,11956421282992330042984,

%U 64584221654333725499376008,438640634423372575622395751944,3658596185733807024739320857622248,36763878323837308563984663576886049704

%N Generalized tangent number d(7,n).

%H Lars Blomberg, <a href="/A064072/b064072.txt">Table of n, a(n) for n = 1..180</a>

%H D. Shanks, <a href="http://dx.doi.org/10.1090/S0025-5718-1967-0223295-5">Generalized Euler and class numbers</a>, Math. Comp. 21 1967 663-688.

%H D. Shanks, <a href="http://dx.doi.org/10.1090/S0025-5718-1968-0227093-9">Corrigenda to: "Generalized Euler and class numbers"</a>, Math. Comp. 22 (1968), 699.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TangentNumber.html">Tangent Number</a>.

%F a(n) = (2*n-1)!*[x^(2*n-1)](sec(7*x)*(-sin(2*x) + sin(4*x) + sin(6*x))). - _Peter Luschny_, Nov 21 2021

%p egf := sec(7*x)*(-sin(2*x) + sin(4*x) + sin(6*x)): ser := series(egf, x, 24):

%p seq((2*n-1)!*coeff(ser, x, 2*n-1), n = 1..10); # _Peter Luschny_, Nov 21 2021

%Y Cf. A064068, A349266, A349264.

%K nonn,easy

%O 1,1

%A _Eric W. Weisstein_, Aug 31 2001

%E Offset changed to 1 by _Lars Blomberg_, Sep 07 2015