A180418 a(n) = ( A000111(p) -(-1)^((p-1)/2) )/p, where p = prime(n).

1, 3, 39, 32163, 1720635, 12345020175, 1530993953307, 44148864630732711, 797213247855503373843915, 281095572810489332134542303, 26242778669866462496740532647355475

Offset

2,2

Links

Amiram Eldar, Table of n, a(n) for n = 2..92

Formula

a(n) = ( A000111(A000040(n)) -A070750(n) )/A000040(n). - R. J. Mathar, Sep 19 2010

Mathematica

t = Range[0, 60]! CoefficientList[Series[Sec@x + Tan@x, {x, 0, 60}], x]; f[n_] := (Rest[t][[Prime@n]] - (-1)^((Prime@n - 1)/2))/Prime@n; Array[f, 11, 2] (* Robert G. Wilson v, Sep 04 2010 *)

Crossrefs

Cf. A000040, A000111, A070750.

Sequence in context: A198411 A367033 A097421 * A166999 A319955 A317484

Adjacent sequences: A180415 A180416 A180417 * A180419 A180420 A180421

Keyword

nonn

Author

Vladimir Shevelev, Sep 03 2010

Extensions

Extended by R. J. Mathar, Sep 19 2010

a(8) onwards from Robert G. Wilson v, Sep 04 2010

Status

approved