OFFSET
1,1
COMMENTS
Essentially the same as A016825.
LINKS
Paolo Xausa, Table of n, a(n) for n = 1..10000
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
a(n) = 4*n + 2. - Max Alekseyev, Mar 03 2007
a(n) = 8*n - a(n-1), with a(1)=6. - Vincenzo Librandi, Aug 08 2010
a(n) = 2*a(n-1) - a(n-2) for n>2; a(1)=6, a(2)=10. - Harvey P. Dale, Mar 06 2012
Simple continued fraction expansion of (e - 1)/(3 - e) = 6 + 1/(10 + 1/(14 + 1/(18 + ...))). - Peter Bala, Dec 12 2025
From Elmo R. Oliveira, Apr 17 2026: (Start)
G.f.: 2*x*(3 - x)/(1 - x)^2.
E.g.f.: 2*(exp(x)*(2*x + 1) - 1).
a(n) = 2*A005408(n). (End)
MATHEMATICA
4*Range[100] + 2 (* Paolo Xausa, Apr 18 2026 *)
PROG
(PARI) a(n) = 4*n+2; \\ Altug Alkan, Jul 23 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Labos Elemer, Aug 08 2002
EXTENSIONS
Definition simplified by Michel Marcus, Jul 26 2018
STATUS
approved
