login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A070290
a(n) = lcm(8,n)/gcd(8,n).
3
8, 4, 24, 2, 40, 12, 56, 1, 72, 20, 88, 6, 104, 28, 120, 2, 136, 36, 152, 10, 168, 44, 184, 3, 200, 52, 216, 14, 232, 60, 248, 4, 264, 68, 280, 18, 296, 76, 312, 5, 328, 84, 344, 22, 360, 92, 376, 6, 392, 100, 408, 26, 424, 108, 440, 7, 456, 116, 472, 30, 488
OFFSET
1,1
FORMULA
a(n) = A109049(n) / A109011(n). - R. J. Mathar, Feb 12 2019
a(n) = 2*a(n-8)-a(n-16). - R. J. Mathar, Feb 12 2019
Sum_{k=1..n} a(k) ~ (293/128)*n^2. - Amiram Eldar, Oct 07 2023
MATHEMATICA
LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, -1}, {8, 4, 24, 2, 40, 12, 56, 1, 72, 20, 88, 6, 104, 28, 120, 2}, 37] (* Georg Fischer, Feb 27 2019 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Amarnath Murthy, May 10 2002
STATUS
approved