A024290 Expansion of tan(tan(x)^2)/2.

0, 1, 8, 256, 17408, 1910656, 309060608, 69341479936, 20585851486208, 7805361597546496, 3678560956503031808, 2108887897093614862336, 1444987869648059585527808, 1166088560957891800314413056, 1094603065624651626325011857408, 1182521392128023075821382696697856

Offset

0,3

Links

Table of n, a(n) for n=0..15.

Formula

a(n) = A009710(n)/2. - Alois P. Heinz, Jan 04 2025

Mathematica

Tan[ Tan[ x ]^2 ]/2 (* Even Part *)

Crossrefs

Cf. A009710.

Sequence in context: A013824 A010044 A374283 * A253165 A140338 A140339

Adjacent sequences: A024287 A024288 A024289 * A024291 A024292 A024293

Keyword

nonn

Author

R. H. Hardin

Status

approved