A109048 a(n) = lcm(n,7).

0, 7, 14, 21, 28, 35, 42, 7, 56, 63, 70, 77, 84, 91, 14, 105, 112, 119, 126, 133, 140, 21, 154, 161, 168, 175, 182, 189, 28, 203, 210, 217, 224, 231, 238, 35, 252, 259, 266, 273, 280, 287, 42, 301, 308, 315, 322, 329, 336, 49, 350, 357, 364, 371, 378, 385, 56

Offset

0,2

Links

Amiram Eldar, Table of n, a(n) for n = 0..10000

Index entries for sequences related to lcm's.

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,2,0,0,0,0,0,0,-1).

Formula

a(n) = n*7/gcd(n,7).

a(n) = 7*A106608(n) = 7*n/A109010(n). - R. J. Mathar, Apr 18 2011

Sum_{k=1..n} a(k) ~ (43/14) * n^2. - Amiram Eldar, Nov 26 2022

Sum_{n>=1} (-1)^(n+1)/a(n) = 13*log(2)/49. - Amiram Eldar, Sep 08 2023

From Elmo R. Oliveira, Jun 02 2026: (Start)

a(n) = 2*a(n-7) - a(n-14).

G.f.: 7*x * (1 + 2*x + 3*x^2 + 4*x^3 + 5*x^4 + 6*x^5 + x^6 + 6*x^7 + 5*x^8 + 4*x^9 + 3*x^10 + 2*x^11 + x^12) / (1 - x^7)^2. (End)

Mathematica

LCM[Range[0, 100], 7] (* Wesley Ivan Hurt, Nov 17 2022 *)

Prog

(SageMath) [lcm(n, 7)for n in range(0, 57)] # Zerinvary Lajos, Jun 09 2009
(Magma) [Lcm(n, 7): n in [0..100]]; // Vincenzo Librandi, Apr 18 2011

Crossrefs

Cf. A106608, A109010, A109042.

Sequence in context: A044847 A282147 A283444 * A289398 A044892 A004959

Adjacent sequences: A109045 A109046 A109047 * A109049 A109050 A109051

Keyword

nonn,easy

Author

Mitch Harris, Jun 18 2005

Status

approved