A248951 Decimal expansion of sum_{n >= 1} (tan(2/n))^2.

9, 0, 4, 3, 5, 2, 8, 6, 0, 8, 6, 5, 8, 2, 1, 1, 1, 5, 2, 6, 5, 6, 3, 8, 2, 7, 4, 7, 2, 9, 5, 8, 9, 9, 5, 7, 9, 1, 5, 1, 3, 3, 3, 5, 7, 1, 9, 8, 7, 1, 5, 0, 4, 1, 3, 9, 2, 4, 2, 5, 1, 2, 7, 8, 0, 7, 1, 9, 3, 6, 3, 4, 5, 9, 9, 6, 4, 4, 8, 8, 9, 4, 6, 7, 5, 4, 6, 4, 2, 4, 8, 4, 7, 2, 8, 5, 9, 7, 0, 9, 8, 5, 2, 2, 4

Offset

1,1

Links

Vaclav Kotesovec, Table of n, a(n) for n = 1..500

Example

9.0435286086582111526563827472958995791513335719871504139242512780719363...

Maple

evalf(sum((tan(2/n))^2, n=1..infinity), 120); # Vaclav Kotesovec, Oct 20 2014

Mathematica

(* N[Sum[Tan[2/n]^2, {n, 1, Infinity}], 120], yields only 24 correct decimals *)

Prog

(PARI) default(realprecision, 120); sumpos(n=1, (tan(2/n))^2) \\ Vaclav Kotesovec, Oct 20 2014

Crossrefs

Cf. A248946, A248947, A248948, A248950.

Sequence in context: A197389 A086307 A215141 * A198226 A195692 A021088

Adjacent sequences: A248948 A248949 A248950 * A248952 A248953 A248954

Keyword

nonn,easy,cons

Author

Clark Kimberling, Oct 18 2014

Status

approved