|
|
A166520
|
|
a(n) = (10*n + 11*(-1)^n + 5)/4.
|
|
1
|
|
|
1, 9, 6, 14, 11, 19, 16, 24, 21, 29, 26, 34, 31, 39, 36, 44, 41, 49, 46, 54, 51, 59, 56, 64, 61, 69, 66, 74, 71, 79, 76, 84, 81, 89, 86, 94, 91, 99, 96, 104, 101, 109, 106, 114, 111, 119, 116, 124, 121, 129, 126, 134, 131, 139, 136, 144, 141, 149, 146, 154, 151, 159
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 5*n - a(n-1) with n>1, a(1)=1.
G.f. -x*(-1-8*x+4*x^2) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Mar 08 2011
E.g.f.: (5*(2*x + 1)*exp(x) + 11*exp(-x) - 16)/4.
a(n) = a(n-1) + a(n-2) - a(n-3). (End)
|
|
MATHEMATICA
|
Table[5 n / 2 + 11 (-1)^n / 4 + 5 / 4, {n, 100}] (* Vincenzo Librandi, Sep 13 2013 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|