A167534 a(n) = 79*n - a(n-1) for n>0, a(0)=9.

9, 70, 88, 149, 167, 228, 246, 307, 325, 386, 404, 465, 483, 544, 562, 623, 641, 702, 720, 781, 799, 860, 878, 939, 957, 1018, 1036, 1097, 1115, 1176, 1194, 1255, 1273, 1334, 1352, 1413, 1431, 1492, 1510, 1571, 1589, 1650, 1668, 1729, 1747, 1808, 1826

Offset: 0

Author

Vincenzo Librandi, Nov 06 2009

Keywords

• nonn
• easy

Comments

Numbers k such that k^2 == 2 (mod 79). - Vincenzo Librandi, Jun 25 2014

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (1,1,-1).

Programs

Magma

[(79/4)-(43/4)*(-1)^n+(79/2)*n: n in [0..50]]; // Vincenzo Librandi, Jun 06 2014

Mathematica

CoefficientList[Series[(9 + 61 x + 9 x^2)/((1 + x) (1 - x)^2), {x, 0, 50}], x] (* Vincenzo Librandi, Jun 06 2014 *)

Formula

G.f.: (9 + 61*x + 9*x^2)/((1 + x)*(1 - x)^2). - Vincenzo Librandi, Jun 06 2014

Sum_{n>=0} (-1)^n/a(n) = cot(9*Pi/79)*Pi/79. - Amiram Eldar, Feb 24 2023

Extensions

Edited by N. J. A. Sloane, Jun 23 2010