A113803 Numbers that are congruent to {3, 11} mod 14.

3, 11, 17, 25, 31, 39, 45, 53, 59, 67, 73, 81, 87, 95, 101, 109, 115, 123, 129, 137, 143, 151, 157, 165, 171, 179, 185, 193, 199, 207, 213, 221, 227, 235, 241, 249, 255, 263, 269, 277, 283, 291, 297, 305, 311, 319, 325, 333, 339, 347, 353, 361, 367

Offset

1,1

Links

Table of n, a(n) for n=1..53.

Formula

a(n) = 14*n - a(n-1) - 14 (with a(1) = 3). - Vincenzo Librandi, Nov 13 2010

From Wolfdieter Lang, Dec 15 2011: (Start)

a(n) = 7*n-(7-(-1)^n)/2.

O.g.f.: x*(3+8*x+3*x^2)/((1+x)*(1-x)^2).

See the Bruno Berselli contribution under A113801. (End)

Sum_{n>=1} (-1)^(n+1)/a(n) = cot(3*Pi/14)*Pi/14. - Amiram Eldar, Dec 30 2021

Mathematica

{3+#, 11+#}&/@(14*Range[0, 30])//Flatten (* Harvey P. Dale, Jun 28 2020 *)

Crossrefs

Third row A113807.

Cf. A008589, A113801, A113802, A113804, A113805, A113806.

Sequence in context: A118590 A136082 A106083 * A226423 A045431 A126691

Adjacent sequences: A113800 A113801 A113802 * A113804 A113805 A113806

Keyword

nonn,easy

Author

Giovanni Teofilatto, Jan 22 2006

Status

approved