OFFSET
0,4
COMMENTS
Essentially same as A001792, except for leading zeros, which motivate the existence of this sequence on its own.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Silvana Ramaj, New Results on Cyclic Compositions and Multicompositions, Master's Thesis, Georgia Southern Univ., 2021. See p. 67.
Index entries for linear recurrences with constant coefficients, signature (4,-4).
FORMULA
G.f. x^2*(1-x)/(1-2*x)^2. - Sergei N. Gladkovskii, Oct 18 2012
G.f.: x^2*( 1 + 2*x*U(0) ) where U(k) = 1 + (k+1)/(2 - 8*x/(4*x + (k+1)/U(k+1))); (continued fraction, 3-step). - Sergei N. Gladkovskii, Oct 19 2012
E.g.f.: x*(exp(2*x) - 1)/4. - Stefano Spezia, Feb 02 2023
Sum_{n>=2} 1/a(n) = 8*log(2) - 4. - Amiram Eldar, Feb 14 2023
MATHEMATICA
CoefficientList[Series[x^2*(1 - x)/(1 - 2*x)^2, {x, 0, 40}], x] (* Vincenzo Librandi, Jan 09 2013 *)
PROG
(PARI) a(n)=n<<(n-3)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
M. F. Hasler, Jan 25 2012
STATUS
approved