A109047 a(n) = lcm(n, 6).

0, 6, 6, 6, 12, 30, 6, 42, 24, 18, 30, 66, 12, 78, 42, 30, 48, 102, 18, 114, 60, 42, 66, 138, 24, 150, 78, 54, 84, 174, 30, 186, 96, 66, 102, 210, 36, 222, 114, 78, 120, 246, 42, 258, 132, 90, 138, 282, 48, 294, 150, 102, 156, 318, 54, 330, 168, 114, 174, 354

Offset: 0

Author

Mitch Harris, Jun 18 2005

Keywords

• nonn
• easy

Links

• Amiram Eldar, Table of n, a(n) for n = 0..10000
• Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,2,0,0,0,0,0,-1).
• Index entries for sequences related to lcm's.

Crossrefs

Cf. A060789, A089128, A109042.

Programs

Magma

[Lcm(n,6): n in [0..100]]; // Vincenzo Librandi, Apr 18 2011

Mathematica

LCM[Range[0,60],6] (* Harvey P. Dale, Nov 20 2022 *)

Sage

[lcm(n,6)for n in range(0, 60)] # Zerinvary Lajos, Jun 07 2009

Formula

a(n) = n*6/gcd(n, 6).

From R. J. Mathar, Apr 18 2011: (Start)

a(n) = 2*a(n-6) - a(n-12) = 6*A060789(n) = 6*n/A089128(n).

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

Sum_{k=1..n} a(k) ~ (7/4) * n^2. - Amiram Eldar, Nov 26 2022