A113805 Numbers that are congruent to {5, 9} mod 14.

5, 9, 19, 23, 33, 37, 47, 51, 61, 65, 75, 79, 89, 93, 103, 107, 117, 121, 131, 135, 145, 149, 159, 163, 173, 177, 187, 191, 201, 205, 215, 219, 229, 233, 243, 247, 257, 261, 271, 275, 285, 289, 299, 303, 313, 317, 327, 331, 341, 345, 355, 359, 369

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) = 5). - Vincenzo Librandi, Nov 13 2010

From Wolfdieter Lang, Dec 15 2011: (Start)

a(n) = 7*n-(7+3*(-1)^n)/2.

O.g.f.: x*(5+4*x+5*x^2)/((1+x)*(1-x)^2).

See the Bruno Berselli contribution under A113801. (End)

Sum_{n>=1} (-1)^(n+1)/a(n) = tan(Pi/7)*Pi/14. - Amiram Eldar, Dec 30 2021

Mathematica

Flatten[Table[14n + {5, 9}, {n, 0, 28}]] (* Alonso del Arte, Dec 15 2011 *)

Crossrefs

Cf. A113801, A113802, A113803, A113804, A113806, A008589, A113807.

Sequence in context: A344746 A226663 A023521 * A160722 A255652 A061202

Adjacent sequences: A113802 A113803 A113804 * A113806 A113807 A113808

Keyword

nonn,easy

Author

Giovanni Teofilatto, Jan 22 2006

Status

approved