OFFSET
1,2
COMMENTS
a(n) = A047452(n-2) for n > 3 because of first formula. - Georg Fischer, Oct 19 2018
LINKS
FORMULA
a(n) = 4n - 10 - (n mod 2), for n>3. - Ralf Stephan, Nov 16 2004
a(n) = a(n-1) + a(n-2) - a(n-3) for n > 3. - Harvey P. Dale, Oct 28 2012
G.f.: x*(1+x+2*x^3+2*x^4+2*x^5)/((1+x)*(1-x)^2). - Georg Fischer, May 15 2019
MATHEMATICA
Join[{1, 2, 3}, Table[4n-10-Mod[n, 2], {n, 4, 60}]] (* or *)
LinearRecurrence[ {1, 1, -1}, {1, 2, 3, 6, 9, 14}, 60]] (* Harvey P. Dale, Oct 28 2012 *)
PROG
(Python)
def A075123(n): return (n-2<<2)-2-(n&1) if n>3 else n # Chai Wah Wu, Mar 30 2024
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Floor van Lamoen, Sep 02 2002
STATUS
approved