OFFSET
3,1
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 3..1000
P. Caron, J.-M. Champarnaud and L. Mignot, Multi-tilde-bar expressions and their automata, Acta Informatica, September 2012, Volume 49, Issue 6, pp 413-436. DOI 10.1007/s00236-012-0167-x. See the sequence t(k).
Index entries for linear recurrences with constant coefficients, signature (1,1,0,-1).
FORMULA
a(3)=5, a(4)=8, a(5)=12; thereafter a(n) = a(n-1) + Pad(n) + 2*Pad(n+1) + 2*Pad(n+2), where Pad() = A000931().
a(n) = a(n-1)+a(n-2)-a(n-4) for n>8. G.f.: x^3*(x^5+2*x^4-x^3-x^2+3*x+5) / ((x-1)*(x^3+x^2-1)). [Colin Barker, Jan 04 2013]
a(n) = a(n-1) + A000931(n+7) for n > 5. - Reinhard Zumkeller, Feb 19 2013
a(n) = a(n-2) + a(n-3) + 9 for n >= 8. - Greg Dresden, May 18 2020
MATHEMATICA
Join[{5, 8}, LinearRecurrence[{1, 1, 0, -1}, {12, 19, 28, 40}, 50]] (* Harvey P. Dale, May 30 2014 *)
PROG
(Haskell)
a220885 n = a220885_list !! (n-3)
a220885_list = 5 : 8 : zs where
zs = 12 : zipWith (+) zs (drop 13 a000931_list)
-- Reinhard Zumkeller, Feb 19 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Dec 29 2012, based on an email from Ludovic Mignot, Dec 27 2012
EXTENSIONS
Simpler definition from Reinhard Zumkeller, Dec 30 2012
STATUS
approved